Provided by: rasmol_2.7.5.2-2_amd64 bug

NAME

       rasmol - Molecular Graphics Visualisation Tool v2.7.5

SYNOPSIS

       rasmol [-nodiplay] [[-format ] filename] [-script scriptfile]

FORMATS

       -pdb        Protein Data Bank
       -mdl        MDL's MOL File Format
       -mol2       Tripos' Sybyl MOL2 Format
       -xyz        MSC's XYZ (XMol) Format
       -mopac      MOPAC Input or Output File Format
       -alchemy    Alchemy File Format
       -charmm     CHARMm File Format
       -cif        IUCr CIF or CIF File Format

NOTICES

       This software has been created from several sources.  Much of the code is from RasMol 2.6,
       as created by Roger Sayle.  The torsion angle code, new POVRAY3 code  and  other  features
       are derived from the RasMol2.6x1 revisions by Arne Mueller.  The Ramachandran printer plot
       code was derived from fisipl created by Frances C.  Bernstein.  See the Protein Data  Bank
       program tape.

       The code to display multiple molecules and to allow bond rotation is derived in large part
       from the UCB mods by Gary Grossman and Marco Molinaro, included with permission of  Eileen
       Lewis of the ModularCHEM Consortium.

       The  CIF  modifications make use of a library based in part on CBFlib by Paul J. Ellis and
       Herbert J. Bernstein.  Parts of CBFlib is loosely based on the CIFPARSE  software  package
       from  the  NDB  at Rutgers university.  Please type the RasMol commands help copying, help
       general, help IUCR, help CBFlib,
        and help CIFPARSE for applicable notices.   Please  type  help  copyright  for  copyright
       notices.   If  you  use  RasMol  V2.6  or an earlier version, type the RasMol command help
       oldnotice.

COPYING

       This version is based directly on RasMol version 2.7.4.2, on  RasMol  verion  2.7.4.2,  on
       RasMol  version  2.7.4,  on  RasMol  version  2.7.3.1,  on RasMol version 2.7.3, on RasMol
       version 2.7.2.1.1, Rasmol version 2.7.2, RasMol version 2.7.1.1 and RasTop version 1.3 and
       indirectly  on the RasMol 2.5-ucb and 2.6-ucb versions and version 2.6_CIF.2, RasMol 2.6x1
       and RasMol_2.6.4.

       RasMol 2.7.5 may be distributed under the terms of the GNU  General  Public  License  (the
       GPL), see

                 http://www.gnu.org/licenses/gpl.txt

       or the file GPL or type the command help GPL

       or  RasMol 2.7.5 may be distributed under the RASMOL license.  See the file NOTICE or type
       the command help RASLIC

       GPL
                                  GNU GENERAL PUBLIC LICENSE
                                     Version 2, June 1991

               Copyright (C) 1989, 1991 Free Software Foundation, Inc.
                                     59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
               Everyone is permitted to copy and distribute verbatim copies
               of this license document, but changing it is not allowed.

                                          Preamble

                The licenses for most software are designed to take away your  freedom  to  share
              and  change  it.   By  contrast,  the  GNU  General  Public  License is intended to
              guarantee your freedom to share and change free software--to make sure the software
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              Software Foundation's software and to any other program  whose  authors  commit  to
              using  it.   (Some  other  Free  Software Foundation software is covered by the GNU
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                                  GNU GENERAL PUBLIC LICENSE
                 TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

                0. This License applies to any program or other  work  which  contains  a  notice
              placed by the copyright holder saying it may be distributed under the terms of this
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              You may charge a fee for the physical act of transferring a copy, and  you  may  at
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              These requirements apply to the modified work as a whole.  If identifiable sections
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                                          NO WARRANTY

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                                   END OF TERMS AND CONDITIONS

                          How to Apply These Terms to Your New Programs

                If  you develop a new program, and you want it to be of the greatest possible use
              to the public, the best way to achieve this is  to  make  it  free  software  which
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              where the full notice is found.

                  <one line to give the program's name and a brief idea of what it does.>
                  Copyright (C) <year>  <name of author>

                  This program is free software; you can redistribute it and/or modify
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                  This program is distributed in the hope that it will be useful,
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              Also add information on how to contact you by electronic and paper mail.

              If the program is interactive, make it output a short  notice  like  this  when  it
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              The  hypothetical  commands `show w' and `show c' should show the appropriate parts
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                Yoyodyne, Inc., hereby disclaims all copyright interest in the program
                `Gnomovision' (which makes passes at compilers) written by James Hacker.

                <signature of Ty Coon>, 1 April 1989
                Ty Coon, President of Vice

              This General Public  License  does  not  permit  incorporating  your  program  into
              proprietary programs.  If your program is a subroutine library, you may consider it
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              License.

       RASLIC If you do not use the GPL, the following license terms apply:

              RasMol License

              Even though the authors of the various documents and software found here have  made
              a  good faith effort to ensure that the documents are correct and that the software
              performs according to its documentation, and we would greatly appreciate hearing of
              any problems you may encounter, the programs and documents any files created by the
              programs  are  provided  **AS  IS**  without  any  warranty  as   to   correctness,
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              THE  RESPONSIBILITY  FOR  ANY  ADVERSE  CONSEQUENCES  FROM  THE  USE OF PROGRAMS OR
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              Subject to your acceptance of the conditions stated above, and your respect for the
              terms  and conditions stated in the notices below, if you are not going to make any
              modifications or create derived works, you are given permission to freely copy  and
              distribute this package, provided you do the following:

                1.   Either  include the complete documentation, especially the file NOTICE, with
              what you distribute or provide a clear indication where people can get  a  copy  of
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                2.   Please  give  credit  where  credit  is  due citing the version and original
              authors properly; and

                3.  Please do not give anyone  the  impression  that  the  original  authors  are
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              If  you  would  like  to  use  major  pieces  of RasMol in some other program, make
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              In addition to the things we discussed above, please do the following:

                4.  Please explain in your documentation how  what  you  did  differs  from  this
              version of RasMol; and

                5.  Please make your modified source code available.

              This version of RasMol is _not_ in the public domain, but it is given freely to the
              community in the hopes of advancing science.  If you make changes, please make them
              in  a  responsible  manner,  and  please  offer us the opportunity to include those
              changes in future versions of RasMol.

       General Notice
              The following notice applies to this work as a whole  and  to  the  works  included
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              *  Creative  endeavors  depend  on the lively exchange of ideas. There are laws and
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              *  Please read the following notice carefully. If you do not understand any portion
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              property rights of the various parties involved, if you do make use of the software
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              * Some of the software and documents included within this software package are  the
              intellectual property of various parties, and placement in this package does not in
              any way imply that any such rights have in any way been waived or diminished.

              * With respect to any software or documents  for  which  a  copyright  exists,  ALL
              RIGHTS ARE RESERVED TO THE OWNERS OF SUCH COPYRIGHT.

              *  Even  though  the  authors of the various documents and software found here have
              made a good faith effort to ensure that the documents  are  correct  and  that  the
              software  performs  according to its documentation, and we would greatly appreciate
              hearing of any problems you may encounter, the programs and documents and any files
              created  by  the  programs  are  provided  **AS  IS**  without  any  warranty as to
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              * THE RESPONSIBILITY FOR ANY ADVERSE CONSEQUENCES  FROM  THE  USE  OF  PROGRAMS  OR
              DOCUMENTS  OR  ANY  FILE  OR FILES CREATED BY USE OF THE PROGRAMS OR DOCUMENTS LIES
              SOLELY WITH THE USERS OF THE PROGRAMS OR DOCUMENTS OR FILE OR FILES  AND  NOT  WITH
              AUTHORS OF THE PROGRAMS OR DOCUMENTS.

              See the files GPL and RASLIC for two alternate ways to license this package.

       RasMol V2.6 Notice
              The following notice applies to RasMol V 2.6 and older RasMol versions.

              Information  in  this  document  is  subject  to change without notice and does not
              represent  a  commitment  on  the  part  of   the   supplier.   This   package   is
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              This product is  not  to  be  used  in  the  planning,  construction,  maintenance,
              operation   or   use  of  any  nuclear  facility  nor  the  flight,  navigation  or
              communication of aircraft or ground support equipment.  The  author  shall  not  be
              liable,  in  whole  or  in  part,  for any claims or damages arising from such use,
              including death, bankruptcy or outbreak of war.

       IUCR Policy
              The IUCr Policy for the Protection and the Promotion  of  the  STAR  File  and  CIF
              Standards for Exchanging and Archiving Electronic Data.

              Overview

              The  Crystallographic  Information  File  (CIF)[1]  is  a  standard for information
              interchange promulgated by the International Union of Crystallography  (IUCr).  CIF
              (Hall,  Allen  & Brown, 1991) is the recommended method for submitting publications
              to Acta Crystallographica Section C and reports of crystal structure determinations
              to  other sections of Acta Crystallographica and many other journals. The syntax of
              a CIF is a subset of the more general STAR File[2] format. The CIF  and  STAR  File
              approaches  are  used increasingly in the structural sciences for data exchange and
              archiving, and are having a significant influence  on  these  activities  in  other
              fields.

              Statement of intent

              The  IUCr's interest in the STAR File is as a general data interchange standard for
              science, and its interest in the CIF, a conformant derivative of the STAR File,  is
              as a concise data exchange and archival standard for crystallography and structural
              science.

              Protection of the standards

              To protect the STAR File and the CIF as standards for interchanging  and  archiving
              electronic data, the IUCr, on behalf of the scientific community,

                 * holds the copyrights on the standards themselves,

                 * owns the associated trademarks and service marks, and

                 * holds a patent on the STAR File.

              These intellectual property rights relate solely to the interchange formats, not to
              the data contained therein, nor to the software used in the generation,  access  or
              manipulation of the data.

              Promotion of the standards

              The  sole  requirement  that  the IUCr, in its protective role, imposes on software
              purporting to process STAR File or CIF data is that the following conditions be met
              prior to sale or distribution.

                 *  Software  claiming  to  read files written to either the STAR File or the CIF
              standard must be able to extract the pertinent data from a file conformant  to  the
              STAR File syntax, or the CIF syntax, respectively.

                 * Software claiming to write files in either the STAR File, or the CIF, standard
              must produce files that are conformant to the STAR File syntax, or the CIF  syntax,
              respectively.

                 * Software claiming to read definitions from a specific data dictionary approved
              by the IUCr must be able to extract any pertinent definition which is conformant to
              the dictionary definition language (DDL)[3] associated with that dictionary.

              The  IUCr,  through  its  Committee  on CIF Standards, will assist any developer to
              verify that software meets these conformance conditions.

              Glossary of terms

              [1] CIF:

              is a data file conformant to the file syntax defined  at  http://www.iucr.org/iucr-
              top/cif/spec/index.html

              [2] STAR File:

              is  a  data file conformant to the file syntax defined at http://www.iucr.org/iucr-
              top/cif/spec/star/index.html

              [3] DDL:

              is a language used  in  a  data  dictionary  to  define  data  items  in  terms  of
              "attributes".  Dictionaries  currently  approved  by the IUCr, and the DDL versions
              used to construct  these  dictionaries,  are  listed  at  http://www.iucr.org/iucr-
              top/cif/spec/ddl/index.html

              Last modified: 30 September 2000

              IUCr Policy Copyright (C) 2000 International Union of Crystallography

       CBFLIB The  following  Disclaimer  Notice  applies to CBFlib V0.1, from which this code in
              part is derived.

              * The items furnished herewith were developed under the  sponsorship  of  the  U.S.
              Government.  Neither  the U.S., nor the U.S. D.O.E., nor the Leland Stanford Junior
              University, nor their employees, makes any warranty, express or implied, or assumes
              any  liability  or  responsibility  for accuracy, completeness or usefulness of any
              information, apparatus, product or process disclosed, or represents  that  its  use
              will not infringe privately-owned rights. Mention of any product, its manufacturer,
              or suppliers shall not, nor is it intended  to,  imply  approval,  disapproval,  or
              fitness for any particular use. The U.S. and the University at all times retain the
              right to use and disseminate the furnished items for any purpose whatsoever.

              Notice 91 02 01

       CIFPARSE
              Portions of this software are loosely based on the CIFPARSE software  package  from
              the NDB at Rutgers University.  See

                 http://ndbserver.rutgers.edu/NDB/mmcif/software

              CIFPARSE  is  part  of the NDBQUERY application, a program component of the Nucleic
              Acid Database Project [ H.  M.  Berman,  W.  K.  Olson,  D.  L.  Beveridge,  J.  K.
              Westbrook,  A. Gelbin, T. Demeny, S. H. Shieh, A. R. Srinivasan, and B.  Schneider.
              (1992). The Nucleic Acid Database: A Comprehensive Relational  Database  of  Three-
              Dimensional   Structures  of  Nucleic  Acids.  Biophys  J.,  63,  751-759.],  whose
              cooperation is gratefully acknowledged, especially in the form of  design  concepts
              created by J. Westbrook.

              Please be aware of the following notice in the CIFPARSE API:

              This  software  is  provided  WITHOUT  WARRANTY OF MERCHANTABILITY OR FITNESS FOR A
              PARTICULAR PURPOSE OR ANY OTHER WARRANTY,  EXPRESS  OR  IMPLIED.  RUTGERS  MAKE  NO
              REPRESENTATION  OR  WARRANTY  THAT  THE  SOFTWARE  WILL  NOT  INFRINGE  ANY PATENT,
              COPYRIGHT OR OTHER PROPRIETARY RIGHT.

DESCRIPTION

       RasMol is a molecular graphics program intended for the visualisation of proteins, nucleic
       acids  and  small  molecules.  The program is aimed at display, teaching and generation of
       publication quality images.   RasMol runs on wide range  of  architectures  and  operating
       systems  including  Microsoft Windows, Apple Macintosh, UNIX and VMS systems. UNIX and VMS
       versions require an 8, 24 or 32 bit colour X Windows display  (X11R4  or  later).   The  X
       Windows  version  of  RasMol  provides  optional  support  for  a  hardware  dials box and
       accelerated shared memory  communication  (via  the  XInput  and  MIT-SHM  extensions)  if
       available on the current X Server.

       The program reads in a molecule coordinate file and interactively displays the molecule on
       the screen in  a  variety  of  colour  schemes  and  molecule  representations.  Currently
       available  representations  include depth-cued wireframes, 'Dreiding' sticks, spacefilling
       (CPK) spheres, ball and stick, solid and strand biomolecular ribbons, atom labels and  dot
       surfaces.

       Up to 5 molecules may be loaded and displayed at once.  Any one or all of
        the molecules may be rotated and translated.

       The  RasMol  help  facility  can  be  accessed  by  typing "help <topic>" or "help <topic>
       <subtopic>" from the command line. A complete list of RasMol commands may be displayed  by
       typing  "help commands". A single question mark may also be used to abbreviate the keyword
       "help".  Please type "help notices" for important notices.

COMMANDS

       RasMol allows the execution of interactive commands typed at the  RasMol>  prompt  in  the
       terminal  window.  Each  command  must  be  given  on  a  separate line. Keywords are case
       insensitive and may be entered in either upper  or  lower  case  letters.  All  whitespace
       characters are ignored except to separate keywords and their arguments.

       All  commands  may  be  prefixed  by a parenthesized atom expression to temporarily select
       certain atoms just for the execution of that one command.  After execution of the command,
       the previous selection is restored except for the commands select , restrict and script.

       The commands/keywords currently recognised by RasMol are given below.

       Backbone
              The RasMol backbone command permits the representation of a polypeptide backbone as
              a series of bonds connecting the adjacent alpha carbons of each  amino  acid  in  a
              chain.  The  display  of these backbone 'bonds' is turned on and off by the command
              parameter in the same way as with the wireframe command. The command  backbone  off
              turns off the selected 'bonds', and backbone on or with a number turns them on. The
              number can be used to specify the cylinder radius of the representation  in  either
              Angstrom or RasMol units. A parameter value of 500 (2.0 Angstroms) or above results
              in a "Parameter value too large" error. Backbone objects may be coloured using  the
              RasMol colour backbone command.

              The  reserved word backbone is also used as a predefined set ("help sets") and as a
              parameter to the set hbond and  set  ssbond  commands.  The  RasMol  command  trace
              renders  a  smoothed backbone, in contrast to backbone which connects alpha carbons
              with straight lines.

              The backbone may be displayed with  dashed  lines  by  use  of  the  backbone  dash
              command.

       Background
              The RasMol background command is used to set the colour of the "canvas" background.
              The colour may be given as either a colour name or a comma separated triple of Red,
              Green  and  Blue  (RGB)  components enclosed in square brackets. Typing the command
              help colours will give a list of the predefined colour names recognised by  RasMol.
              When  running  under  X  Windows,  RasMol also recognises colours in the X server's
              colour name database.

              The background command is synonymous with the RasMol set background command.

       Bond   The RasMol command bond <number>  <number>  +  adds  the  designated  bond  to  the
              drawing,  increasing  the  bond order if the bond already exists.  The command bond
              <number> <number> pick selects the two atoms specified by the atom  serial  numbers
              as  the  two  ends  of  a bond around which the rotate bond <angle> command will be
              applied.  If no bond exists, it is created.

              Rotation around a previously picked bond  may  be  specified  by  the  rotate  bond
              <angle>  command,  or  may also be controlled with the mouse, using the bond rotate
              on/off or the equivalent rotate bond on/off commands.

       Bulgarian
              The RasMol Bulgarian command sets the menus and messages to the Bulgarian versions.

              This command may not work correctly unless appropriate fonts have  been  installed.
              The  commands Bulgarian, Chinese, English, French, Italian, Russian and Spanish may
              be used to select Bulgarian, Chinese, English, French, Italian,  Japanese,  Russian
              and Spanish menus and messages if the appropriate fonts have been installed.

       Cartoon
              The  RasMol  cartoon  command  does  a  display of a molecule ribbons as Richardson
              (MolScript) style protein  cartoons,  implemented  as  thick  (deep)  ribbons.  The
              easiest  way to obtain a cartoon representation of a protein is to use the Cartoons
              option on the Display menu. The cartoon command represents the  currently  selected
              residues  as  a  deep ribbon with width specified by the command's argument.  Using
              the command without a parameter results in the ribbon's width being taken from  the
              protein's secondary structure, as described in the ribbons command. By default, the
              C-termini of beta-sheets are displayed as arrow heads.  This  may  be  enabled  and
              disabled  using the set cartoons command.  The depth of the cartoon may be adjusted
              using the set cartoons <number> command.  The  set  cartoons  command  without  any
              parameters returns these two options to their default values.

       Centre The  RasMol centre command defines the point about which the rotate command and the
              scroll bars rotate the current molecule. Without a  parameter  the  centre  command
              resets  the  centre  of rotation to be the centre of gravity of the molecule. If an
              atom expression is specified, RasMol rotates  the  molecule  about  the  centre  of
              gravity of the set of atoms specified by the expression. Hence, if a single atom is
              specified by the expression, that atom will remain 'stationary' during rotations.

              Type help expression for more information on RasMol atom expressions.

              Alternatively the centring may be given as a comma separated triple of [CenX, CenY,
              CenZ]  offsets  in  RasMol units (1/250 of an Angstrom) from the centre of gravity.
              The triple must be enclosed in square brackets.

              The optional forms centre ... translate and  centre  ...  center  may  be  used  to
              specify  use  of  a translated centre of rotation (not necessarily in the centre of
              the canvas) or a centre of rotation which is placed at the centre  of  the  canvas.
              Starting with RasMol 2.7.2, the default is to center the new axis on the canvas.

       Chinese
              The RasMol Chinese command sets the menus and messages to the Chinese versions.

              This  command  may not work correctly unless appropriate fonts have been installed.
              The commands Bulgarian, Chinese, English, French, Italian, Russian and Spanish  may
              be  used  to select Bulgarian, Chinese, English, French, Italian, Japanese, Russian
              and Spanish menus and messages if the appropriate fonts have been installed.

       Clipboard
              The RasMol clipboard command places a copy of the currently displayed image on  the
              local  graphics 'clipboard'. Note: this command is not yet supported on UNIX or VMS
              machines. It is intended to make transferring images  between  applications  easier
              under Microsoft Windows or on an Apple Macintosh.

              When  using  RasMol  on  a UNIX or VMS system this functionality may be achieved by
              generating a raster image in a format that can be read  by  the  receiving  program
              using the RasMol write command.

       Colour Colour the atoms (or other objects) of the selected region. The colour may be given
              as either a colour name or a comma separated triple of Red, Green  and  Blue  (RGB)
              components enclosed in square brackets. Typing the command help colours will give a
              list of all the predefined colour names recognised by RasMol.

              Allowed objects are atoms, bonds, backbone, ribbons, labels, dots, hbonds, map, and
              ssbonds.   If  no  object  is specified, the default keyword atom is assumed.  Some
              colour schemes are defined for certain object types. The colour scheme none can  be
              applied  to  all  objects  except atoms and dots, stating that the selected objects
              have no colour of their own, but use the colour of their associated atoms (i.e. the
              atoms  they  connect).   Atom  objects  can  also be coloured by alt, amino, chain,
              charge, cpk, group, model, shapely, structure, temperature or user.  Hydrogen bonds
              can also be coloured by type and dot surfaces can also be coloured by electrostatic
              potential.  For more information type help colour <colour>.   Map  objects  may  be
              coloured by specific color of by nearest atom.

       ColourMode
              ColourMode  allows  the  user  to  switch  between  using the new colour method. At
              present, the new coloring technique is the same as the old  one,  but  to  preserve
              compatibility for older scripts it may be wise to add a "colormode on" near the top
              of your script somewhere, if the script was designed for version 2.7.3 of RasMol or
              earlier.  The  new  color  method,  when  completed,  aims to fix a few bugs in the
              coloring routines.

       Connect
              The  RasMol  connect  command  is  used  to  force  RasMol  to  (re)calculate   the
              connectivity  of  the  current  molecule.   If  the  original  input file contained
              connectivity information, this is discarded. The command connect false uses a  fast
              heuristic algorithm that is suitable for determining bonding in large bio-molecules
              such as proteins and nucleic acids. The command connect true  uses  a  slower  more
              accurate  algorithm  based  upon  covalent  radii  that  is  more suitable to small
              molecules containing inorganic elements or strained rings.  If  no  parameters  are
              given, RasMol determines which algorithm to use based on the number of atoms in the
              input file. Greater than 255 atoms causes RasMol to use the faster  implementation.
              This  is  the  method  used  to determine bonding, if necessary, when a molecule is
              first read in using the load command.

       Defer  The RasMol defer command adds the command given to the macro with given name, if no
              name is given, the command is added to the macro with a blank name. The command zap
              is a special case. In that case the macro is  erased.  If  no  name  is  given  the
              command must begin with a selection, e.g.  defer (selection).spacefill

              The  deferred  commands  accumulated under the given name can be executed using the
              execute command

       Define The RasMol define command allows the user to associate an arbitrary  set  of  atoms
              with  a  unique  identifier. This allows the definition of user-defined sets. These
              sets are declared statically, i.e. once defined the contents  of  the  set  do  not
              change,  even if the expression defining them depends on the current transformation
              and representation of the molecule.

       Depth  The RasMol depth command enables, disables or positions the back-clipping plane  of
              the molecule. The program only draws those portions of the molecule that are closer
              to the viewer than the clipping plane.  Integer values range from zero at the  very
              back  of  the  molecule  to  100  which  is  completely  in  front of the molecule.
              Intermediate values determine the percentage of the molecule to be drawn.

              This command interacts with the slab <value> command, which clips to the front of a
              given z-clipping plane.

       Dots   The RasMol dots command is used to generate a van der Waals' dot surface around the
              currently selected atoms. Dot surfaces display regularly spaced points on a  sphere
              of  van  der  Waals'  radius about each selected atom. Dots that would are 'buried'
              within the van der Waals' radius of any  other  atom  (selected  or  not)  are  not
              displayed.   The  command  dots on deletes any existing dot surface and generates a
              dots surface around the currently selected atom set with a default dot  density  of
              100.  The command dots off deletes any existing dot surface. The dot density may be
              specified by  providing  a  numeric  parameter  between  1  and  1000.  This  value
              approximately  corresponds  to  the number of dots on the surface of a medium sized
              atom.

              By default, the colour of each point on a dot surface is the colour of its  closest
              atom  at the time the surface is generated. The colour of the whole dot surface may
              be changed using the colour dots command.

       Echo   The RasMol echo command is used to display a message in the RasMol command/terminal
              window.   The  string  parameter  may  optionally  be  delimited  in  double  quote
              characters. If no parameter is specified, the echo command displays a  blank  line.
              This command is particularly useful for displaying text from within a RasMol script
              file.

       English
              The RasMol English command sets the menus and messages to the English versions.

              This command may not work correctly unless appropriate fonts have  been  installed.
              The  commands Bulgarian, Chinese, English, French, Italian, Russian and Spanish may
              be used to select Bulgarian, Chinese, English, French, Italian,  Japanese,  Russian
              and Spanish menus and messages if the appropriate fonts have been installed.

       Execute
              The RasMol execute command:

              1.  saves the old poise of the molecule (translation, rotation and zoom)

              2. executes the specified macro suppressing both screen updates and recording

              3.  animates  motion  of the newly rendered molecule linearly from the old poise to
              the new poise

              The macro must have been previously defined by calls to the defer command.

              The animation of the motion depends on the prior settings of the record command.

       French The RasMol French command sets the menus and messages to the French versions.

              This command may not work correctly unless appropriate fonts have  been  installed.
              The  commands Bulgarian, Chinese, English, French, Italian, Russian and Spanish may
              be used to select Bulgarian, Chinese, English, French, Italian,  Japanese,  Russian
              and Spanish menus and messages if the appropriate fonts have been installed.

       HBonds The  RasMol  hbond command is used to represent the hydrogen bonding of the protein
              molecule's  backbone.  This  information  is  useful  in  assessing  the  protein's
              secondary  structure.  Hydrogen  bonds  are  represented  as either dotted lines or
              cylinders between the donor and acceptor residues. The first time the hbond command
              is used, the program searches the structure of the molecule to find hydrogen bonded
              residues and reports the number of  bonds  to  the  user.  The  command  hbonds  on
              displays  the  selected 'bonds' as dotted lines, and the hbonds off turns off their
              display. The colour of hbond objects may be changed by the  colour  hbond  command.
              Initially, each hydrogen bond has the colours of its connected atoms.

              By default the dotted lines are drawn between the accepting oxygen and the donating
              nitrogen. By using the set  hbonds  command  the  alpha  carbon  positions  of  the
              appropriate  residues may be used instead. This is especially useful when examining
              proteins in backbone representation.

       Help   The RasMol help command provides on-line help on the given topic.

       Italian
              The RasMol Italian command sets the menus and messages to the Italian versions.

              This command may not work correctly unless appropriate fonts have  been  installed.
              The  commands Bulgarian, Chinese, English, French, Italian, Russian and Spanish may
              be used to select Bulgarian, Chinese, English, French, Italian,  Japanese,  Russian
              and Spanish menus and messages if the appropriate fonts have been installed.

       Japanese
              The RasMol Japanese command sets the menus and messages to the Japanese versions.

              This  command  may not work correctly unless appropriate fonts have been installed.
              The commands Bulgarian, Chinese, English, French, Italian, Russian and Spanish  may
              be  used  to select Bulgarian, Chinese, English, French, Italian, Japanese, Russian
              and Spanish menus and messages if the appropriate fonts have been installed.

       Label  The RasMol label command allows an arbitrary formatted text string to be associated
              with  each  currently  selected  atom.  This string may contain embedded 'expansion
              specifiers' which display properties of  the  atom  being  labelled.  An  expansion
              specifier  consists  of  a  '%' character followed by a single alphabetic character
              specifying the property to be displayed.  An actual '%' character may be  displayed
              by using the expansion specifier '%%'.

              Atom  labelling for the currently selected atoms may be turned off with the command
              label off.  By default, if no string is given as a parameter,  RasMol  uses  labels
              appropriate for the current molecule.

              The colour of each label may be changed using the colour label command. By default,
              each label is drawn in the same colour as the atom to which  it  is  attached.  The
              size  and  spacing  of  the  displayed  text  may be changed using the set fontsize
              command.  The width of the strokes in the displayed text may be changed
               using the set fontstroke
               command.

       Load   Load a molecule coordinate file into RasMol. Valid molecule file  formats  are  pdb
              (Protein  Data  Bank  format),  mdl  (Molecular  Design Limited's MOL file format),
              alchemy (Tripos' Alchemy file format),  mol2  (Tripos'  Sybyl  Mol2  file  format),
              charmm  (CHARMm  file  format),  xyz  (MSC's  XMol  XYZ  file format), mopac (J. P.
              Stewart's MOPAC file format) or cif (IUCr CIF or mmCIF file  format).  If  no  file
              format  is  specified, PDB, CIF, or mmCIF is assumed by default. Up to 20 molecules
              may be loaded at a time.  If CHEM_COMP ligand models are included in an mmCIF file,
              they  will  be  loaded as NMR models, first giving the all the NMR models for model
              coordinates if specified and then  giving  all  the  NMR  models  for  ideal  model
              coordinates.

              To  delete  a  molecule  prior  to  loading another use the RasMol zap command.  To
              select a molecule for manipulation use the RasMol molecule <n> command.

              The load command selects all the atoms in the molecule, centres it  on  the  screen
              and renders it as a CPK coloured wireframe model. If the molecule contains no bonds
              (i.e. contains only alpha carbons), it is drawn as an alpha carbon backbone. If the
              file  specifies  fewer  bonds  than atoms, RasMol determines connectivity using the
              connect command.

              The load inline command also allows the storing of atom coordinates in  scripts  to
              allow better integration with WWW browsers. A load command executed inside a script
              file may specify the keyword inline instead of a conventional filename. This option
              specifies  that the coordinates of the molecule to load are stored in the same file
              as the currently executing commands.

       Map    The RasMol map commands manipulate electron density maps in coordination  with  the
              display of molecules.  These commands are very memory intensive and may not work on
              machines with limited memory.  Each molecule may have as  many  maps  as  available
              memory  permits.   Maps  may  be read from files or generated from Gaussian density
              distributions around atoms.

              map colour, to colour a map according to a given colour scheme,  map  generate,  to
              generate a map from selected atoms based on pseudo-Gaussians, map level, to set the
              contouring level for selected maps, map load, to load a map from a file,  map  mask
              to  designate  a  mask for the selected maps, map resolution, to set the resolution
              for contouring selected maps, map restrict, to select  one  or  more  maps  and  to
              disable all others, map save, to save map information to a file, map scale, control
              the scaling of pseudo-Gaussians when generating maps, map select, to select one  or
              more  maps,  map  show,  to display information about one or more maps or about the
              parameters to be used in generating or loading the next map, map  spacing,  to  set
              the  spacing betwen contour lines of selected maps, map spread, to set the variance
              of the Gaussians for map generation as a fraction of the atomic radius, and map zap
              to delete previously generated or loaded maps.

              The  effect  of  map  generate  and  map  load commands is modified by the map mask
              command which limits the portion of the display space that can  be  considered  for
              display of maps.

       Map colour
              The  RasMol map colour command colours the selected maps according to the specified
              colour scheme.  The colour scheme may be  a  colour  name  or  and  RBG  triple  in
              brackets,  or  the keyword atom to cause the map points to be coloured by the color
              of the nearest atom.

       Map generate
              The RasMol map generate command generates a map from whatever atoms  are  currently
              selected,  by  summing  electron  densities approximated by Gaussian distributions.
              The height of each Gaussian is determined by the setting of the map scale  command.
              In  the  default of map scale true, each Gaussian has a height proportional element
              type of the atom.  If the optional 'LRSurf' parameter is  given  or  if  map  scale
              false has been executed, each Gaussian is scaled so that the Gaussian contour level
              1 is at the van der Waals radius.  In either case a standard  deviation  determined
              by  the most recently specified spread or resolution is used.  If a non-zero spread
              has been given the radius of the atom is multiplied  by  the  spread  to  find  the
              standard  deviation.   The  default is 2/3rds.  If a resolution has been given, the
              spread is inferred as 2/3rds of the resolution.

              For example, if the resolution is given as 1., and the atom in question is a Carbon
              with  a  van  der  Waals  radius of 468 RasMol units (1.87 Angstroms), the inferred
              spead is .6667, and the standard  deviation  of  the  Gaussian  is  taken  as  1.25
              Angstroms.

              If the spread has been set to zero, the spread for each atom is determined from the
              van der Waals radius and the probe atom radius to simulate the  effect  of  a  Lee-
              Richards surface.

              If  no  specific  map  was given by the map selector, the new map is given the next
              available map number.

              If a specific map was given by the map selector, the new map replaces that map.  If
              more  than  one  map was given by the map selector, the new map replaces the lowest
              numbered of the selected maps.  In any case  the  new  map  becomes  the  currently
              selected map.

              The  map  is  displayed  as  dots,  mesh  or  a  surface, depending on the last map
              rendering mode selected or the mode selected on the command itself.

       Map level
              The RasMol map level command  sets  the  contour  level  to  be  used  in  creating
              subsequent  representations  of  generated  or loaded maps.  If the keyword MEAN in
              used the level is relative to the mean of the map data.   Otherwise  the  level  is
              absolute.

              In general, a lower level results in a map containing more of the displayed volume,
              while a higher level results in a map containing less of the displayed volume.

       Map load
              The RasMol map load command loads a map file into RasMol.  The  valid  formats  are
              CCP4 map format and imgCIF format.

              If  no  specific  map  was given by the map selector, the new map is given the next
              available map number.

              If a specific map was given by the map selector, the new map replaces that map.  If
              more  than  one  map was given by the map selector, the new map replaces the lowest
              numbered of the selected maps.  In any case  the  new  map  becomes  the  currently
              selected map.

              The map is displayed as dots, mesh or a surface depending on the last map rendering
              mode selected.

       Map mask
              The RasMol map mask command specifies a mask to be used to limit the display  space
              to  be  used  for  making  representations of other maps or removes an earlier mask
              specification.

              The 'selected' option indicates that the mask is to be created from  the  currently
              selected atoms.  The '<number>' option indicates that the mask is to be copied from
              the map of  the  number  specified.   The  'none'  option  removes  the  previously
              specified mask, if any.

              The  map  selector  specifies  the map or maps to which the specified mask will the
              applied.  For example, 'map  next  mask  selected'  specifies  that  the  currently
              selected  atoms are to be used to generate a mask to be applied to any maps created
              by subsequent 'map load' or 'map generate' commands.

              Any map may be used as a mask.  The portions of the mask map greater than  than  or
              equal to the average value of the mask map allow the values of the map being masked
              to be used as given.  The portions of the mask map lower than the average value  of
              the mask map cause the values of the map being masked to be treated as if they were
              equal to the lowest data value of the map being masked.

       Map resolution
              The RasMol map resolution command specifies the resolution in RasMol units or, if a
              number  containing a decimal point is given, the resolution in Angstroms to be used
              in generating and in representing maps.

              The resolution is used at the map spacing for representations of  maps,  indicating
              the  separation  between  contour levels (see the map spacing command) and to infer
              the map spread to be used in generated maps from selected atoms (see the map spread
              command).  The map spread is set to two thirds of the specified resolution.

       Map restrict
              The  RasMol  map  restrict  command selects particular maps to make them active for
              subsequent map commands.  This is similar to  the  map  select  command,  but  does
              disables the display of the maps that were not selected.

       Map save
              The RasMol map save command saves an imgCIF map file.

              If  no  specific map was given by the map selector, the currently selected maps and
              their masks are written to the file, one map and mask pair per data block.

       Map scale
              The RasMol map scale command selects the scaling of  pseudo-Gaussians  in  the  map
              generate  commands.   In  the default of map scale true, each Gaussian has a height
              proportional element type of the atom.  If map scale false has been executed,  each
              Gaussian  is  scaled  so  that the Gaussian contour level 1 is at the van der Waals
              radius.  In either case a  standard  deviation  determined  by  the  most  recently
              specified spread or resolution is used.

       Map select
              The  RasMol  map  select  command  selects  particular maps to make them active for
              subsequent map commands.  This is similar to the map restrict command, but does not
              disable the display of the maps that were not selected.

              If the optional atom parameter is given, the command selects the atoms with centres
              closest to the map points.  The radius of  the  search  may  be  specified  by  the
              parameter  search_radius.  The default is to look for atoms within 4 Angstroms plus
              the probe radius.  If the optional within parameter is given, the new selection  is
              taken  from  within  the currently selected atoms.  If the options add parameter is
              given, the new selection is added to the currently selected atoms.  The default  is
              to search within all atoms.

       Map show
              The  RasMol map show command causes information about the maps specified by the map
              selector to be written to the command window.

       Map spacing
              The RasMol map spacing command specifies the spacing to  be  used  between  contour
              lines in creating representations of maps.  The spacing is typically
               given in Angstroms with a decimal point, but may also be specified in RasMol units
              (250ths of an Angstom) as an integer.  For maps loaded  in  grid  coordinates  that
              spacing is parallel to the cell edges.  The default spacing is one half Angstrom.

       Map spread
              The  RasMol  map  spread command specifies the reciprocal of the number of standard
              deviations per radius to be used in generating maps as sums of  Gaussians  centered
              on atomic positions.  The default spread is one two thirds (i.e. each radius covers
              1.5 standard deviations).

              If the spread has been set to zero, the spread for each atom is determined from the
              van  der  Waals  radius  and the probe atom radius to simulate the effect of a Lee-
              Richards surface.

       Map zap
              The RasMol map zap command  removes  the  data  and  representations  of  the  maps
              specified  by the map selector.  The map numbers of maps that have not been removed
              are not changed.

       Molecule
              The RasMol molecule command selects one of up to 5 previously loaded molecules  for
              active  manipulation.   While  all  the  molcules  are displayed and may be rotated
              collectively (see the rotate all command), only one molecule  at  a  time  time  is
              active for manipulation by the commands which control the details of rendering.

       Monitor
              The  RasMol  monitor  command  allows  the display of distance monitors. A distance
              monitor is a dashed (dotted) line between an arbitrary pair  of  atoms,  optionally
              labelled  by  the  distance  between  them.   The  RasMol  command monitor <number>
              <number> adds such a distance monitor between the two atoms specified by  the  atom
              serial numbers given as parameters

              Distance  monitors  are  turned  off  with  the  command monitors off.  By default,
              monitors display the distance between its two end points as a label at  the  centre
              of  the  monitor.  These  distance  labels  may  be turned off with the command set
              monitors off, and re-enabled with the command set monitors  on.   Like  most  other
              representations, the colour of a monitor is taken from the colour of its end points
              unless specified by the colour monitors command.

              Distance monitors may also be added to a molecule  interactively  with  the  mouse,
              using  the  set  picking  monitor command. Clicking on an atom results in its being
              identified on the rasmol command line. In addition every atom picked  increments  a
              modulo  counter such that, in monitor mode, every second atom displays the distance
              between this atom and the previous one. The shift key may be used to form  distance
              monitors between a fixed atom and several consecutive positions. A distance monitor
              may also be removed (toggled) by selecting the appropriate pair of atom end  points
              a second time.

       Notoggle
              The  RasMol NoToggle command enables or disables the use of the toggle ability that
              is used by some of the other RasMol commands.  When no boolean value is  specified,
              NoToggle  mode is ENABLED.  When NoToggle mode is ENABLED, all toggle functionality
              is DISABLED. To turn it off, one must explicitly set notoggle off.

              Some commands which use the toggle feature are: ColourMode.   More  functions  that
              utilize this capability may be added at a later date.

       Pause  The  RasMol pause command is used in script files to stop the script file for local
              manipulation by a mouse, until any key is pushed to restart the script file.   Wait
              is  synonymous  with pause.  This command may be executed in RasMol script files to
              suspend the sequential execution of commands and allow  the  user  to  examine  the
              current image.   When RasMol executes a pause command in a script file, it suspends
              execution of the rest of the file, refreshes the image on the screen and allows the
              manipulation  of  the  image  using  the mouse and scroll  bars, or resizing of the
              graphics window.  Once a key is pressed, control returns to the script file at  the
              line  following the pause command.  While a script is suspended the molecule may be
              rotated, translated, scaled, slabbed and picked as usual, but all menu commands are
              disabled.

       Play   The  RasMol  play  command specifies the recording medium from which to play back a
              movie.  The playback frame start time is given in seconds to millisecond precision.
              Since  we are working on computers, the medium is specified as a set of files, each
              marked with the playback frame start time in milliseconds as part of the name.  The
              place  in  the  name  at  which  to  look  for  the  playback  frame  start time in
              milliseconds is marked by the characters "ssssss" with  an  appropriate  number  of
              digits.   RasMol  accepts  either upper or lower case s's or decimal digits to mark
              the place for the time.  The play off and play eject  commands  effectively  remove
              the specified medium from use. If no medium is specified, play off suspends playing
              and play on resumes playing.  Normally play starts immediately and runs to the  end
              of  the  medium.  However,  if play off and/or or some combination of play from and
              play until is entered before play type medium, those settings will be used.

              As of release 2.7.5, RasMol support play from scripts and data files.

       Print  The RasMol print command sends the currently displayed image to the  local  default
              printer  using  the operating system's native printer driver. Note: this command is
              not yet supported under UNIX or VMS. It is intended to take advantage of  Microsoft
              Windows  and Apple Macintosh printer drivers. For example, this allows images to be
              printed directly on a dot matrix printer.

              When using RasMol on a UNIX or VMS system this functionality  may  be  achieved  by
              either  generating  a  PostScript  file  using  the RasMol write ps or write vectps
              commands and printing that or generating a raster image file and using a utility to
              dump that to the local printer.

       Quit   Exit  from  the  RasMol  program. The RasMol commands exit and quit are synonymous,
              except within nested scripts.  In that  case,  exit  terminates  only  the  current
              level, while quit terminates all nested levels of scripts.

       Record The  RasMol  record command specifies the recording medium to hold the movie. Since
              we are working on computers, the medium is specified as a template  for  a  set  of
              files,  each marked with the playback frame start time in milliseconds (rather than
              as seconds to avoid embedding a decimal point) as part of the name.  The  place  in
              the  name  to  be  replaced  with  the playback frame start time in milliseconds is
              marked by the characters "ssssss" with an  appropriate  number  of  digits.  RasMol
              accepts  either upper or lower case s's or decimal digits to mark the place for the
              time.  The record off commands remove the specified medium from use. If  no  medium
              is  specified,  record  off suspends recording and record on resumes recording with
              the next available time on the same medium. The screen is the  default  medium  and
              is,  by  default, on. Writing to disk must be explicitly specified so that the disk
              does not get filled up unintentionally. The type of a recording medium  may  be  an
              image type such as gif, pict or png to record the actual screen images or script to
              record the RasMol commands used to generate the frames.

              Normally recording starts at playback frame  start  time  0  seconds.   A  non-zero
              starting time in seconds can be specified with the record from command as in record
              from 25 or record from 37.25 to help in organizing scenes of movies to be assembled
              later  in  an appropriate order.  The record until command allows an upper limit to
              be set on recording time in seconds.  The default is to have no limit. Issuing  the
              commands

              record from 600

              record until 1800

              would  result  in  a  20  minute  movie segment intended to start 10 minutes into a
              longer movie.  These commands allow control over rewriting selected time segments.

       Refresh
              The RasMol refresh command redraws the current image.  This is useful in scripts to
              ensure application of a complex list of parameter changes.

       Renumber
              The  RasMol  renumber command sequentially numbers the residues in a macromolecular
              chain.  The optional parameter specifies the value of  the  first  residue  in  the
              sequence.  By default, this value is one. For proteins, each amino acid is numbered
              consecutively from the N terminus to the C terminus. For nucleic acids,  each  base
              is  numbered  from  the  5'  terminus to the 3' terminus. All chains in the current
              database are renumbered and gaps in the original sequence are ignored. The starting
              value for numbering may be negative.

       Reset  The RasMol reset command restores the original viewing transformation and centre of
              rotation. The scale is set to its default value, zoom 100, the centre  of  rotation
              is  set  to the geometric centre of the currently loaded molecule, centre all, this
              centre is translated to the middle of the screen  and  the  viewpoint  set  to  the
              default orientation.

              This  command  should  not be mistaken for the RasMol zap command which deletes the
              currently stored molecule, returning the program to its initial state.

       Restrict
              The RasMol restrict command both defines  the  currently  selected  region  of  the
              molecule  and  disables the representation of (most of) those parts of the molecule
              no longer selected.  All subsequent RasMol commands that modify a molecule's colour
              or  representation  affect  only  the currently selected region. The parameter of a
              restrict command is a RasMol atom expression that is evaluated for  every  atom  of
              the  current  molecule.  This command is very similar to the RasMol select command,
              except restrict disables the wireframe, spacefill and backbone  representations  in
              the non-selected region.

              Type  "help  expression"  for  more  information  on RasMol atom expressions or see
              section Atom Expressions.

       Ribbons
              The RasMol ribbons command displays the currently loaded protein or nucleic acid as
              a  smooth  solid  "ribbon"  surface passing along the backbone of the protein.  The
              ribbon is drawn between each amino acid whose alpha carbon is  currently  selected.
              The  colour  of  the  ribbon is changed by the RasMol colour ribbon command. If the
              current ribbon colour is none (the default), the colour is  taken  from  the  alpha
              carbon at each position along its length.

              The width of the ribbon at each position is determined by the optional parameter in
              the usual RasMol units. By default the width  of  the  ribbon  is  taken  from  the
              secondary  structure of the protein or a constant value of 720 (2.88 Angstroms) for
              nucleic acids.  The default width of protein alpha helices and beta sheets  is  380
              (1.52  Angstroms)  and 100 (0.4 Angstroms) for turns and random coil. The secondary
              structure assignment is either from the PDB  file  or  calculated  using  the  DSSP
              algorithm  as  used by the structure command. This command is similar to the RasMol
              command strands which  renders  the  biomolecular  ribbon  as  parallel  depth-cued
              curves.

       Rotate Rotate  the  molecule  about  the  specified  axis.   Permitted values for the axis
              parameter are "x", "y", "z" and "bond".  The integer parameter states the angle  in
              degrees for the structure to be rotated. For the X and Y axes, positive values move
              the closest point up and  right,  and  negative  values  move  it  down  and  left,
              respectively.  For  the  Z  axis, a positive rotation acts clockwise and a negative
              angle anti-clockwise.

              Alternatively, this command may be used to specify which  rotations  the  mouse  or
              dials  will  control.   If  rotate bond true is selected, the horizontal scroll bar
              will control rotation around the axis selected by the bond src  dst  pick  command.
              If  rotate  all true is selected, and multiple molecules have been loaded, then all
              molecules will rotate together.  In all other cases, the mouseand dials control the
              the rotation of the molecule selected by the molecule n command.

       Russian
              The RasMol Russian command sets the menus and messages to the Russian versions.

              This  command  may not work correctly unless appropriate fonts have been installed.
              The commands Bulgarian, Chinese, English, French, Italian, Russian and Spanish  may
              be  used  to select Bulgarian, Chinese, English, French, Italian, Japanese, Russian
              and Spanish menus and messages if the appropriate fonts have been installed.

       Save   Save the currently selected set of  atoms  in  a  Protein  Data  Bank  (PDB),  MDL,
              Alchemy(tm)  or  XYZ  format  file.   The  distinction between this command and the
              RasMol write command has been dropped. The only difference is that without a format
              specifier  the  save command generates a PDB file and the write command generates a
              GIF image.

       Script The RasMol script command reads a set of RasMol commands sequentially from  a  text
              file  and  executes  them.  This  allows  sequences of commonly used commands to be
              stored and performed by single command. A RasMol script file may contain a  further
              script  command  up  to  a maximum "depth" of 10, allowing complicated sequences of
              actions to be executed. RasMol ignores all characters after the first '#' character
              on  each  line  allowing  the  scripts to be annotated. Script files are often also
              annotated using the RasMol echo command.

              The most common way to generate a RasMol script file is to use the write script  or
              write  rasmol  commands  to  output  the  sequence  of  commands that are needed to
              regenerate  the  current  view,  representation  and  colouring  of  the  currently
              displayed molecule.

              The RasMol command source is synonymous with the script command.

       Select Define  the  currently  selected  region  of  the  molecule.  All subsequent RasMol
              commands that manipulate a molecule or modify its  colour  or  representation  only
              affect the currently selected region. The parameter of a select command is a RasMol
              expression that is evaluated for every atom of the current molecule. The  currently
              selected  (active) region of the molecule are those atoms that cause the expression
              to evaluate true. To select the whole molecule use the RasMol command  select  all.
              The  behaviour  of  the  select command without any parameters is determined by the
              RasMol hetero and hydrogen parameters.

              Type "help expression" for more information  on  RasMol  atom  expressions  or  see
              section Atom Expressions.

       Set    The RasMol set command allows the user to alter various internal program parameters
              such as those controlling rendering options. Each parameter  has  its  own  set  or
              permissible parameter options. Typically, omitting the parameter option resets that
              parameter to its default value. A list of valid parameter names is given below.

       Show   The RasMol show command display details of  the  status  of  the  currently  loaded
              molecule.  The  command show information lists the molecule's name, classification,
              PDB code and the number of atoms, chains, groups it contains.  If hydrogen bonding,
              disulphide  bridges  or  secondary  structure  have  been determined, the number of
              hbonds, ssbonds, helices, ladders and turns are also displayed,  respectively.  The
              command  show  centre  shows  any  non-zero centering values selected by the centre
              [CenX, CenY, CenZ] command. The command show phipsi shows the phi and psi angles of
              the  currently  selected  residues  and  the omega angles of cis peptide bonds. The
              command show RamPrint (or 'show RPP' or  'show  RamachandranPrinterPlot')  shows  a
              simple  Ramachandran  printer  plot  in  the  style  of  Frances Bernstein's fisipl
              program.  The command show rotation (or 'show rot' or  'show  'rotate')  shows  the
              currently  selected values of z, y, x and bond rotations, if any.  The command show
              selected (or 'show selected group' or 'show  selected  chain'  or   'show  selected
              atom'  ) shows the groups (default), chains or atoms of the current selection.  The
              command show sequence lists the residues that comprise each chain of the  molecule.
              The  command show symmetry shows the space group and unit cell of the molecule. The
              command show translation shows any non-zero  translation  values  selected  by  the
              translate  <axis>  <value>  command.  The command show zoom shows any non-zero zoom
              value selected by the zoom <value> command.

       Slab   The RasMol slab command enables, disables or positions the z-clipping plane of  the
              molecule.  The  program  only draws those portions of the molecule that are further
              from the viewer than the slabbing plane.  Integer values range  from  zero  at  the
              very  back  of  the  molecule  to 100 which is completely in front of the molecule.
              Intermediate values determine the percentage of the molecule to be drawn.

              This command interacts with the depth <value> command, which clips to the rear of a
              given z-clipping plane.

       Spacefill
              The  RasMol  spacefill  command  is used to represent all of the currently selected
              atoms as solid spheres. This command is used to produce both  union-of-spheres  and
              ball-and-stick  models  of  a  molecule.  The command, spacefill true, the default,
              represents each atom as a sphere of van der Waals radius.   The  command  spacefill
              off  turns  off the representation of the selected atom as spheres. A sphere radius
              may be specified as an integer in  RasMol  units  (1/250th  Angstrom)  or  a  value
              containing  a decimal point. A value of 500 (2.0 Angstroms) or greater results in a
              "Parameter value too large" error.

              The temperature option sets the radius of each sphere to the value  stored  in  its
              temperature  field.  Zero or negative values have no effect and values greater than
              2.0 are truncated to 2.0.  The user option allows the radius of each sphere  to  be
              specified  by  additional lines in the molecule's PDB file using Raster 3D's COLOUR
              record extension.

              The RasMol command cpk is synonymous with the spacefill command.

              The RasMol command cpknew is synonymous with the spacefill command, except  that  a
              slightly different set of colours is used.

       Spanish
              The RasMol Spanish command sets the menus and messages to the Spanish versions.

              This  command  may not work correctly unless appropriate fonts have been installed.
              The commands Bulgarian, Chinese, English, French, Italian, Russian and Spanish  may
              be  used  to select Bulgarian, Chinese, English, French, Italian, Japanese, Russian
              and Spanish menus and messages if the appropriate fonts have been installed.

       SSBonds
              The RasMol ssbonds command is used to  represent  the  disulphide  bridges  of  the
              protein  molecule  as  either  dotted  lines  or  cylinders  between  the connected
              cysteines. The first time that the ssbonds command is used,  the  program  searches
              the  structure of the protein to find half-cysteine pairs (cysteines whose sulphurs
              are within 3 Angstroms of each other) and reports the  number  of  bridges  to  the
              user. The command ssbonds on displays the selected "bonds" as dotted lines, and the
              command ssbonds off disables the display of ssbonds in the currently selected area.
              Selection  of  disulphide bridges is identical to normal bonds, and may be adjusted
              using the RasMol set bondmode command.  The  colour  of  disulphide  bonds  may  be
              changed  using the colour ssbonds command. By default, each disulphide bond has the
              colours of its connected atoms.

              By default disulphide bonds are drawn between the sulphur atoms within the cysteine
              groups.  By  using  the  set  ssbonds  command the position of the cysteine's alpha
              carbons may be used instead.

       Star   The RasMol star command is used to represent all of the currently selected atoms as
              stars  (six  strokes,  one  each  in  the  x, -x, y, -y, z and -z directions).  The
              commands select not bonded followed by star 75 are useful to mark unbonded atoms in
              a  wireframe display with less overhead than provided by spacefill 75.  This can be
              done automatically for all subsequent  wireframe  displays  with  the  command  set
              bondmode not bonded.

              The  command  star  true,  the default, represents each atom as a star with strokes
              length equal to van  der  Waals  radius.   The  command  star  off  turns  off  the
              representation of the selected atom as stars. A star stroke length may be specified
              as an integer in RasMol units (1/250th Angstrom) or a value  containing  a  decimal
              point.  A value of 500 (2.0 Angstroms) or greater results in a "Parameter value too
              large" error.

              The temperature option sets the stroke length of each star to the value  stored  in
              its  temperature  field.  Zero or negative values have no effect and values greater
              than 2.0 are truncated to 2.0.  The user option allows the stroke  length  of  each
              star  to  be  specified by additional lines in the molecule's PDB file using Raster
              3D's COLOUR record extension.

              The RasMol spacefill command can be used for more artistic rendering  of  atoms  as
              spheres.

       Stereo The  RasMol  stereo  command provides side-by-side stereo display of images. Stereo
              viewing of a molecule may be turned on (and off) either by  selecting  Stereo  from
              the Options menu, or by typing the commands stereo on or stereo off.

              Starting  with  RasMol  version  2.7.2.1, the Stereo menu selection and the command
              stereo without arguments cycle from the initial state of stereo off to stereo on in
              cross-eyed mode to stereo on in wall-eyed mode and then back to stereo off.

              The  separation angle between the two views may be adjusted with the set stereo [-]
              <number> command, where positive values result in crossed eye viewing and  negative
              values in relaxed (wall-eyed) viewing.  The inclusion of [-] <number> in the stereo
              command, as for example  in  stereo  3  or  stereo  -5,  also  controls  angle  and
              direction.

              The  stereo  command  is  only partially implemented. When stereo is turned on, the
              image is not properly recentred. (This can be done with a translate x -<number>
               command.)  It is not supported in vector PostScript output files, is not saved  by
              the  write  script  command,  and  in  general  is not yet properly interfaced with
              several other features of the program.

       Strands
              The RasMol strands command displays the currently loaded protein or nucleic acid as
              a  smooth  "ribbon" of depth-cued curves passing along the backbone of the protein.
              The ribbon is composed of a number of strands that  run  parallel  to  one  another
              along  the  peptide  plane  of each residue. The ribbon is drawn between each amino
              acid whose alpha carbon is currently selected.  The colour of the ribbon is changed
              by  the  RasMol  colour  ribbon  command. If the current ribbon colour is none (the
              default), the colour is taken from the alpha carbon  at  each  position  along  its
              length.  The  central and outermost strands may be coloured independently using the
              colour ribbon1 and colour ribbon2 commands, respectively. The number of strands  in
              the ribbon may be altered using the RasMol set strands command.

              The width of the ribbon at each position is determined by the optional parameter in
              the usual RasMol units. By default the width  of  the  ribbon  is  taken  from  the
              secondary  structure  of  the  protein or a constant value of 720 for nucleic acids
              (which produces a ribbon 2.88 Angstroms wide).  The default width of protein  alpha
              helices  and  beta sheets is 380 (1.52 Angstroms) and 100 (0.4 Angstroms) for turns
              and random coil. The secondary structure assignment is either from the PDB file  or
              calculated  using the DSSP algorithm as used by the structure command. This command
              is similar to the RasMol command ribbons which renders the biomolecular ribbon as a
              smooth shaded surface.

       Structure
              The  RasMol  structure  command  calculates secondary structure assignments for the
              currently loaded protein. If the original PDB file contained structural  assignment
              records (HELIX, SHEET and TURN) these are discarded.  Initially, the hydrogen bonds
              of the current molecule are found, if this hasn't been done already. The  secondary
              structure  is  then  determined  using  Kabsch  and  Sander's  DSSP algorithm. Once
              finished the program reports the number of helices, strands and turns found.

       Surface
              The RasMol surface command renders a Lee-Richards molecular surface resulting  from
              rolling  a  probe atom on the selected atoms.  The value given specifies the radius
              of the probe.  If given in the first form, the evolute of the surface of the  probe
              is shown (the solvent excluded surface).  If given in the second form, the envelope
              of the positions of the center of  the  probe  is  shown  (the  solvent  accessible
              surface).

       Trace  The RasMol trace command displays a smooth spline between  consecutive alpha carbon
              positions.  This spline does not pass exactly through the alpha carbon position  of
              each  residue,  but   follows the same path as ribbons, strands and cartoons.  Note
              that residues may be displayed  as  ribbons,  strands,  cartoons  or  as  a  trace.
              Enabling  one  of these representations disables the others. However, a residue may
              be displayed simultaneously as backbone and as one of  the  above  representations.
              This  may  change  in  future  versions of RasMol.  Prior to version 2.6, trace was
              synonymous with backbone.

              Trace temperature displays the backbone as a wider  cylinder  at  high  temperature
              factors   and   thinner   at   lower.   This  representation  is  useful  to  X-ray
              crystallographers and NMR spectroscopists.

       Translate
              The RasMol translate command moves the position of the centre of  the  molecule  on
              the  screen.  The  axis  parameter specifies along which axis the molecule is to be
              moved and the integer parameter specifies the absolute  position  of  the  molecule
              centre  from the middle of the screen.  Permitted values for the axis parameter are
              "x", "y" and  "z".   Displacement  values  must  be  between  -100  and  100  which
              correspond  to  moving  the  current  molecule  just off the screen. A positive "x"
              displacement moves the molecule to the right, and a positive "y" displacement moves
              the  molecule down the screen. The pair of commands translate x 0 and translate y 0
              centres the molecule on the screen.

       UnBond The RasMol command unbond <number> <number> removes the designated  bond  from  the
              drawing.

              The  command  unbond without arguments removes a bond previously picked by the bond
              <number> <number> pick command.

       Wireframe
              The RasMol wireframe command represents each bond within the selected region of the
              molecule  as  a  cylinder,  a  line or a depth-cued vector. The display of bonds as
              depth-cued vectors (drawn darker the further away from the viewer) is turned on  by
              the  command  wireframe  or  wireframe  on.   The  selected  bonds are displayed as
              cylinders by specifying a radius either as an integer in RasMol units or containing
              a  decimal point as a value in Angstroms.  A parameter value of 500 (2.0 Angstroms)
              or above results in an "Parameter value too large" error.  Bonds  may  be  coloured
              using the colour bonds command.

              If  the  selected  bonds  involved atoms of alternate conformers then the bonds are
              narrowed in the middle to a radius of .8 of the specified radius (or to the  radius
              specified as the optional second parameter).

              Non-bonded atoms, which could become invisible in an ordinary wireframe display can
              be marked by a preceding set bondmode not  bonded  command.   If  nearly  co-linear
              bonds  to  atoms  cause them to be difficult to see in a wireframe display, the set
              bondmode all command will add markers for all atoms in subsequent wireframe command
              executions.

       Write  Write  the  current image to a file in a standard format. Currently supported image
              file formats include bmp (Microsoft bitmap) and gif (Compuserve  GIF),  iris  (IRIS
              RGB),  ppm  (Portable  Pixmap),  ras  (Sun  rasterfile),  ps and epsf (Encapsulated
              PostScript), monops (Monochrome Encapsulated PostScript), pict (Apple PICT), vectps
              (Vector  Postscript).   The  write  command  may  also  be used to generate command
              scripts for other graphics programs. The format script writes out a file containing
              the  RasMol  script  commands  to reproduce the current image. The format molscript
              writes out the commands required to render the current  view  of  the  molecule  as
              ribbons  in Per Kraulis' Molscript program and the format kinemage the commands for
              David Richardson's program Mage.  The following  formats  are  useful  for  further
              processing:  povray (POVRay 2), povray3 (POVRay 3 -- under development), vrml (VRML
              file).  Finally, several formats are provided to provide phi-psi data  for  listing
              or for phipsi (phi-psi data as an annotated list with cis omegas), ramachan and RDF
              and RamachandranDataFile (phi-psi data as columns of numbers for gnuplot), RPP  and
              RamachandranPrinterPlot (phi-psi data as a printer plot).

              The  distinction between this command and the RasMol save command has been dropped.
              The only difference is that without a format specifier the save command generates a
              PDB file and the write command generates a GIF image.

       Zap    Deletes  the  contents  of  the  current database and resets parameter variables to
              their initial default state.

       Zoom   Change the magnification of  the  currently  displayed  image.  Boolean  parameters
              either  magnify  or  reset  the  scale  of  current  molecule. An integer parameter
              specifies the desired magnification as a  percentage  of  the  default  scale.  The
              minimum  parameter  value  is 10; the maximum parameter value is dependent upon the
              size of the molecule being displayed. For medium sized proteins this is about 500.

SET PARAMETERS

       RasMol has a number of internal parameters that may be modified  using  the  set  command.
       These  parameters  control a number of program options such as rendering options and mouse
       button mappings.

           picking         play.fps        radius          record.aps

       Set Ambient
              The RasMol ambient  parameter  is  used  to  control  the  amount  of  ambient  (or
              surrounding)  light  in  the scene. The ambient value must be between 0 and 100. It
              controls the percentage intensity of the darkest shade of an object.  For  a  solid
              object,  this  is the intensity of surfaces facing away from the light source or in
              shadow.  For depth-cued objects this is the intensity of objects furthest from  the
              viewer.

              This  parameter  is  commonly  used  to  correct for monitors with different "gamma
              values" (brightness), to change how light or dark a  hardcopy  image  appears  when
              printed or to alter the feeling of depth for wireframe or ribbon representations.

       Set Axes
              The RasMol axes parameter controls the display of orthogonal coordinate axes on the
              current display. The coordinate axes are those used in the molecule data file,  and
              the  origin  is  the centre of the molecule's bounding box. The set axes command is
              similar to the commands set boundbox and set unitcell that display the bounding box
              and the crystallographic unit cell, respectively.

       Set Backfade
              The  RasMol  backfade  parameter  is  used  to  control  backfade  to the specified
              background colour, rather than black.  This  is  controlled  by  the  commands  set
              backfade on and set backfade off.  For example, this may be used to generate depth-
              cued images that fade to white, rather than black.

       Set Background
              The RasMol background  parameter  is  used  to  set  the  colour  of  the  "canvas"
              background.  The  colour  may be given as either a colour name or a comma separated
              triple of Red, Green, Blue (RGB) components enclosed in square brackets. Typing the
              command  help colours will give a list of the predefined colour names recognised by
              RasMol.  When running under X Windows, RasMol also  recognises  colours  in  the  X
              server's colour name database.

              The command set background is synonymous with the RasMol command background.

       Set BondMode
              The  RasMol  set  bondmode command controls the mechanism used to select individual
              bonds and modifies the  display  of  bonded  and  non-bonded  atoms  by  subsequent
              wireframe commands.

              When  using  the  select and restrict commands, a given bond will be selected if i)
              the bondmode is or and either of the  connected  atoms  is  selected,  or  ii)  the
              bondmode  is  and  and  both  atoms  connected  by  the bond are selected. Hence an
              individual bond may be uniquely identified by using the command  set  bondmode  and
              and then uniquely selecting the atoms at both ends.

              The bondmode [all | none | not bonded] commands add star 75 or spacefill 75 markers
              for the designated atoms to wireframe displays.  Stars are used when the  specified
              wireframe radius is zero.

       Set Bonds
              The RasMol bonds parameter is used to control display of double and triple bonds as
              multiple  lines or cylinders.  Currently bond orders are only read  from   MDL  Mol
              files,  Sybyl  Mol2  format files, Tripos Alchemy format files, CIF and mmCIF,  and
              suitable PDB files.  Double (and triple)  bonds are specified in some  PDB files by
              specifying  a  given bond twice  (and three times) in CONECT records.  The  command
              set bonds on enables the display of bond orders, and  the  command  set  bonds  off
              disables them.

       Set BoundBox
              The  RasMol  boundbox  parameter  controls  the  display  of the current molecule's
              bounding box on the display. The bounding box is  orthogonal  to  the  data  file's
              original  coordinate  axes. The set boundbox command is similar to the commands set
              axes and set unitcell that display orthogonal coordinate axes and the bounding box,
              respectively.

       Set Cartoon
              The  RasMol  cartoon parameter is used to control display of the cartoon version of
              the ribbons display.  By default, the C-termini of  beta-sheets  are  displayed  as
              arrow  heads.  This  may  be  enabled and disabled using the set cartoons <boolean>
              command. The depth of the cartoon may  be  adjusted  using  the  cartoons  <number>
              command.  The set cartoons command without any parameters returns these two options
              to
               their default values.

       Set CisAngle
              The RasMol cisangle parameter controls the cutoff angle for identifying cis peptide
               bonds.  If no value is given, the cutoff is set to 90 degrees.

       Set Display
              This command controls the display mode  within  RasMol.  By  default,  set  display
              normal,  RasMol  displays the molecule in the representation specified by the user.
              The command set display selected changes the display mode such that the molecule is
              temporarily drawn so as to indicate currently selected portion of the molecule. The
              user specified  colour  scheme  and  representation  remains  unchanged.   In  this
              representation  all  selected  atoms are shown in yellow and all non selected atoms
              are shown in blue. The colour of the background is also changed to a dark  grey  to
              indicate  the  change  of  display  mode.   This  command is typically only used by
              external Graphical User Interfaces (GUIs).

       Set FontSize
              The RasMol set fontsize command is used to control the size of the characters  that
              form  atom  labels. This value corresponds to the height of the displayed character
              in pixels. The maximum value of fontsize is 48 pixels, and the default value  is  8
              pixels  high.   Fixed or proportional spacing may be selected by appending the "FS"
              or "PS" modifiers, respectively.  The default is "FS".  To display atom  labels  on
              the  screen  use  the  RasMol  label  command and to change the colour of displayed
              labels, use the colour labels command.

       Set FontStroke
              The RasMol set fontstroke command is used to control the size of the  stroke  width
              of  the  characters  that  form atom labels.  This value is the radius in pixels of
              cylinders used to form the strokes.  The special value of "0" is the  default  used
              for  the  normal  single  pixel  stroke  width,  which allows for rapid drawing and
              rotation of the image.  Non-zero values are provided to  allow  for  more  artistic
              atom labels for publication at the expense of extra time in rendering the image.

              When  wider  strokes  are used, a larger font size is recommend, e.g.  by using the
              RasMol set fontsize 24 PS command, followed by set fontstroke 2

              To display atom labels on the screen use the RasMol label command,  and  to  change
              the colour of displayed labels use the colour labels command.

       Set HBonds
              The RasMol hbonds parameter determines whether hydrogen bonds are drawn between the
              donor and acceptor atoms of the hydrogen bond, set hbonds sidechain or between  the
              alpha carbon atoms of the protein backbone and between the phosphorous atoms of the
              nucleic acid backbone, set hbonds backbone.  The actual display of  hydrogen  bonds
              is  controlled  by the hbonds command. Drawing hydrogen bonds between protein alpha
              carbons or nucleic acid phosphorous atoms is useful when the rest of  the  molecule
              is  shown  in only a schematic representation such as backbone, ribbons or strands.
              This parameter is similar to the RasMol ssbonds parameter.

       Set Hetero
              The RasMol hetero parameter is used to modify the 'default' behaviour of the RasMol
              select  command,  i.e.  the  behaviour  of select without any parameters. When this
              value is false, the default select region does not include any heterogeneous  atoms
              (refer  to the predefined set hetero ). When this value is true, the default select
              region may contain hetero atoms. This parameter is similar to the  RasMol  hydrogen
              parameter which determines whether hydrogen atoms should be included in the default
              set. If both hetero and  hydrogen  are  true,  select  without  any  parameters  is
              equivalent to select all.

       Set HourGlass
              The RasMol hourglass parameter allows the user to enable and disable the use of the
              'hour glass' cursor used by RasMol to indicate that the program is  currently  busy
              drawing  the next frame. The command set hourglass on enables the indicator, whilst
              set hourglass off prevents RasMol from changing the cursor.  This  is  useful  when
              spinning  the  molecule, running a sequence of commands from a script file or using
              interprocess communication to execute complex sequences of commands. In these cases
              a 'flashing' cursor may be distracting.

       Set Hydrogen
              The  RasMol  hydrogen  parameter  is  used to modify the "default" behaviour of the
              RasMol select command, i.e. the behaviour of select without  any  parameters.  When
              this  value  is  false,  the  default  select region does not include any hydrogen,
              deuterium or tritium atoms (refer to the predefined set hydrogen ). When this value
              is  true,  the  default select region may contain hydrogen atoms. This parameter is
              similar to the RasMol hetero parameter which determines whether heterogeneous atoms
              should be included in the default set. If both hydrogen and hetero are true, select
              without any parameters is equivalent to select all.

       Set Kinemage
              The RasMol set kinemage command controls the amount of detail stored in a  Kinemage
              output  file  generated  by  the RasMol write kinemage command. The output kinemage
              files are intended to  be  displayed  by  David  Richardson's  Mage  program.   set
              kinemage  false, the default, only stores the currently displayed representation in
              the generated output file. The command set kinemage true, generates a more  complex
              Kinemage  that  contains both the wireframe and backbone representations as well as
              the coordinate axes, bounding box and crystal unit cell.

       Set Menus
              The RasMol set menus command enables the canvas window's menu buttons or menu  bar.
              This  command  is  typically only used by graphical user interfaces or to create as
              large an image as possible when using Microsoft Windows.

       Set Monitor
              The RasMol set monitor command enables monitors.  The distance monitor  labels  may
              be turned off with the command set monitor off, and re-enabled with the command set
              monitor on.

       Set Mouse
              The RasMol set mouse command sets the rotation, translation,  scaling  and  zooming
              mouse  bindings.  The default value is rasmol which is suitable for two button mice
              (for three button mice the second and third buttons are synonymous);  X-Y  rotation
              is  controlled  by  the first button, and X-Y translation by the second. Additional
              functions are controlled by holding a modifier key on the  keyboard.   [Shift]  and
              the  first  button  performs  scaling,  [shift]  and  the second button performs Z-
              rotation, and [control] and the first mouse button controls the clipping plane. The
              insight  and  quanta  options provide the same mouse bindings as other packages for
              experienced users.

       Set Picking
              The RasMol set picking series of commands affects how a user may  interact  with  a
              molecule displayed on the screen in RasMol.

              Enabling/Disabling  Atom Identification Picking: Clicking on an atom with the mouse
              results in identification and the display of its residue name, residue number, atom
              name,  atom  serial  number  and  chain in the command window. This behavior may be
              disabled with the command set picking  none  and  restored  with  the  command  set
              picking  ident.   The  command set picking coord adds the atomic coordinates of the
              atom to the display.

              Disabling picking, by using set picking off is  useful  when  executing  the  pause
              command  in  RasMol  scripts  as it prevents the display of spurious message on the
              command line while the script is suspended.

              Measuring Distances, Angles and Torsions:  Interactive  measurement  of  distances,
              angles  and  torsions  is  achieved  using  the commands: set picking distance, set
              picking monitor, set picking angle and set picking torsion, respectively. In  these
              modes,  clicking  on  an  atom results in it being identified on the rasmol command
              line. In addition every atom picked  increments  a  modulo  counter  such  that  in
              distance  mode,  every  second  atom  displays  the  distance (or distance monitor)
              between this atom and the previous one. In angle mode, every  third  atom  displays
              the  angle  between  the previous three atoms and in torsion mode every fourth atom
              displays the torsion between the last four atoms. By holding  down  the  shift  key
              while  picking  an  atom,  this  modulo  counter is not incremented and allows, for
              example, the distances of consecutive atoms from a fixed atom to be displayed.  See
              the  monitor  command  for how to control the display of distance monitor lines and
              labels.

              Labelling Atoms with the Mouse: The mouse may also be used to toggle the display of
              an atom label on a given atom. The RasMol command set picking label removes a label
              from a picked atom if it already has one or displays a concise label at  that  atom
              position otherwise.

              Centring  Rotation  with  the  Mouse: A molecule may be centred on a specified atom
              position using the RasMol commands set picking centre or set  picking  center.   In
              this mode, picking an atom causes all futher rotations to be about that point.

              Picking  a  Bond  as a Rotation Axis: Any bond may be picked as an axis of rotation
              for the portion of the molecule beyond the  second  atom  selected.   This  feature
              should  be  used with caution, since, naturally, it changes the conformation of the
              molecule.  After executing set picking bond or using the equivalent "Pick Bond"  in
              the  "Settings"  menu,  a  bond to be rotated is picked with the same sort of mouse
              clicks as are used for picking atoms for a  distance  measurement.   Normally  this
              should  be  done where a bond exists, but if no bond exists, it will be added.  The
              bond cannot be used for rotation if it is part of a ring of any  size.   All  bonds
              selected  for  rotation  are  remembered so that they can be properly reported when
              writing a script, but only the most recently selected bond may be actively rotated.

              Enabling Atom/Group/Chain Selection  Picking:  Atoms,  groups  and  chains  may  be
              selected  (as  if  with the select command), with the set picking atom, set picking
              group, set picking chain commands.  For each of these commands, the shift  key  may
              be  used  to have a new selection added to the old, and the control key may be used
              to have a new selection deleted from the old. When the set picking atom command  is
              given,  the  mouse  can be used to pick or to drag a box around the atoms for which
              selection is desired.  When the set picking group command is given, picking any  an
              atom  will  cause  selection  of  all  atoms which agree in residue number with the
              picked atom, even if in different chains.  When the set picking  chain  command  is
              given,  picking  any  atom  will  cause selection of all atoms which agree in chain
              identifier with the picked atom.

       Set Play
              The RasMol set play.fps command gives the number of frames per second for  playback
              by the play command (default 24 frames per second).

              In  the  current  release  of  RasMol,  the  play  timing is not controlled by this
              parameter.

       Set Radius
              The RasMol set radius command is used to alter the behaviour  of  the  RasMol  dots
              command  depending  upon the value of the solvent parameter.  When solvent is true,
              the radius parameter controls whether a true van der Waals' surface is generated by
              the dots command. If the value of radius is anything other than zero, that value is
              used as the radius of each atom instead of its true vdW value. When  the  value  of
              solvent  is  true,  this  parameter determines the 'probe sphere' (solvent) radius.
              The parameter may be given as an integer in rasmol units or  containing  a  decimal
              point  in Angstroms. The default value of this parameter is determined by the value
              of solvent and changing solvent resets radius to its new default value.

       Set Record
              The RasMol set record.aps gives the maximum on-screen  velocity  in  Angstroms  per
              second in animating translations, rotations and zooms (default 10 A/second).

              The  RasMol  set record.aps command gives number of frames per second for recording
              by the record command (default 24 frames per second).

              The RasMol set record.dwell command sets the time in seconds to dwell on  a  change
              in appearance (default .5 sec).

       Set ShadePower
              The  shadepower  parameter  (adopted  from RasTop) determines the shade repartition
              (the contrast) used in rendering solid  objects.  This  value  between  0  and  100
              adjusts  shading  on  an  object  surface oriented along the direction to the light
              source.  Changing the shadepower parameter does  not  change  the  maximum  or  the
              minimum values of this shading, as does changing the ambient parameter.  A value of
              100 concentrates the light on the top of spheres, giving a highly specular,  glassy
              rendering (see the specpower parameter).  A value of 0 distributes the light on the
              entire object.

              This implementation of shadepower differs from the one in RasTop only in the choice
              of range (0 to 100 versus -20 to 20 in RasTop).

       Set Shadow
              The  RasMol  set  shadow  command enables and disables ray-tracing of the currently
              rendered image.  Currently only the spacefilling representation is shadowed or  can
              cast   shadows.  Enabling  shadowing  will  automatically  disable  the  Z-clipping
              (slabbing) plane using the command slab off.   Ray-tracing  typically  takes  about
              several  seconds  for a moderately sized protein.  It is recommended that shadowing
              be normally disabled whilst the molecule is being transformed or  manipulated,  and
              only  enabled  once  an  appropriate  viewpoint  is  selected, to provide a greater
              impression of depth.

       Set SlabMode
              The RasMol slabmode parameter controls the rendering method of objects cut  by  the
              slabbing  (z-clipping)  plane.  Valid  slabmode  parameters  are  "reject", "half",
              "hollow", "solid" and "section".

       Set Solvent
              The RasMol set solvent command is used to control the behaviour of the RasMol  dots
              command. Depending upon the value of the solvent parameter, the dots command either
              generates a van der Waals' or a solvent accessible  surface  around  the  currently
              selected  set  of  atoms. Changing this parameter automatically resets the value of
              the RasMol radius parameter.  The command set solvent  false,  the  default  value,
              indicates that a van der Waals' surface should be generated and resets the value of
              radius to zero. The command  set  solvent  true  indicates  that  a  'Connolly'  or
              'Richards'  solvent  accessible  surface  should  be  drawn  and  sets  the  radius
              parameter, the solvent radius, to 1.2 Angstroms (or 300 RasMol units).

       Set Specular
              The RasMol set specular command  enables  and  disables  the  display  of  specular
              highlights  on  solid  objects drawn by RasMol. Specular highlights appear as white
              reflections of the light source on the surface of the object.  The  current  RasMol
              implementation uses an approximation function to generate this highlight.

              The  specular  highlights  on the surfaces of solid objects may be altered by using
              the specular  reflection  coefficient,  which  is  altered  using  the  RasMol  set
              specpower command.

       Set SpecPower
              The  specpower  parameter  determines  the  shininess  of solid objects rendered by
              RasMol. This value between 0 and 100 adjusts the  reflection  coefficient  used  in
              specular  highlight  calculations. The specular highlights are enabled and disabled
              by the RasMol set specular command. Values around 20 or 30 produce plastic  looking
              surfaces.   High  values  represent more shiny surfaces such as metals, while lower
              values produce more diffuse/dull surfaces.

       Set SSBonds
              The RasMol ssbonds  parameter  determines  whether  disulphide  bridges  are  drawn
              between  the  sulphur  atoms  in  the  sidechain (the default) or between the alpha
              carbon atoms in the backbone of the  cysteines  residues.  The  actual  display  of
              disulphide bridges is controlled by the ssbonds command. Drawing disulphide bridges
              between alpha carbons is useful when the rest of the protein is  shown  in  only  a
              schematic  representation  such as backbone, ribbons or strands.  This parameter is
              similar to the RasMol hbonds parameter.

       Set Stereo
              The RasMol set stereo parameter controls the separation between the left and  right
              images. Turning stereo on and off doesn't reposition the centre of the molecule.

              Stereo  viewing of a molecule may be turned on (and off) either by selecting Stereo
              from the Options menu, or by typing the commands stereo on or stereo off.

              The separation angle between the two views may be adjusted with the set stereo  [-]
              <number>  command, where positive values result in crossed eye viewing and negative
              values in relaxed (wall-eyed) viewing. Currently, stereo viewing is  not  supported
              in vector PostScript output files.

       Set Strands
              The  RasMol  strands  parameter  controls  the  number of parallel strands that are
              displayed in the ribbon representations of proteins.  The  permissible  values  for
              this  parameter  are  1,  2,  3,  4, 5 and 9. The default value is 5. The number of
              strands is constant for all ribbons being displayed.   However,  the  ribbon  width
              (the  separation  between  strands) may be controlled on a residue by residue basis
              using the RasMol ribbons command.

       Set Transparent
              The RasMol transparent parameter controls the writing of transparent  GIFs  by  the
              write gif <filename> command.  This may be controlled by the set transparent on and
              set transparent off commands.

       Set UnitCell
              The RasMol unitcell parameter controls the display  of  the  crystallographic  unit
              cell  on  the  current display. The crystal cell is only enabled if the appropriate
              crystal symmetry information is contained in the PDB, CIF or mmCIF data  file.  The
              RasMol  command show symmetry display details of the crystal's space group and unit
              cell axes. The set unitcell command is similar to the commands  set  axes  and  set
              boundbox   that   display   orthogonal   coordinate  axes  and  the  bounding  box,
              respectively.

       Set VectPS
              The RasMol vectps parameter is use to control the way in  which  the  RasMol  write
              command generates vector PostScript output files. The command set vectps on enables
              the use of black outlines around spheres and  cylinder  bonds  producing  "cartoon-
              like"  high  resolution  output.  However,  the  current  implementation  of RasMol
              incorrectly cartoons spheres that are intersected by more than  one  other  sphere.
              Hence  "ball  and  stick"  models are rendered correctly but not large spacefilling
              spheres models. Cartoon outlines can be disabled, the default, by the  command  set
              vectps off.

       Set Write
              The  RasMol  write parameter controls the use of the save and write commands within
              scripts, but it may only be executed from the command line.  By default, this value
              is  false,  prohibiting the generation of files in any scripts executed at start-up
              (such as those launched from a WWW browser). However, animators may start up RasMol
              interactively:  type  set write on and then execute a script to generate each frame
              using the source command.

ATOM EXPRESSIONS

       RasMol atom expressions uniquely identify an arbitrary group of atoms within  a  molecule.
       Atom expressions are composed of either primitive expressions, predefined sets, comparison
       operators, within expressions, or logical (boolean) combinations of the  above  expression
       types.

       The  logical  operators  allow complex queries to be constructed out of simpler ones using
       the standard boolean connectives and, or and not.  These may be abbreviated by the symbols
       "&", "|" and "!", respectively. Parentheses (brackets) may be used to alter the precedence
       of the operators. For convenience, a comma may also be used for boolean disjunction.

       The atom expression is evaluated for each atom, hence protein and backbone selects protein
       backbone atoms, not the protein and [nucleic] acid backbone atoms!

       Primitive Expressions
              RasMol   primitive   expressions  are  the  fundamental  building  blocks  of  atom
              expressions. There are two types of primitive expression.  The first type  is  used
              to identify a given residue number or range of residue numbers. A single residue is
              identified by its number (position in the sequence), and a range  is  specified  by
              lower  and upper bounds separated by a hyphen character. For example select 5,6,7,8
              is also select 5-8.  Note that this  selects  the  given  residue  numbers  in  all
              macromolecule chains.

              The  second  type  of primitive expression specifies a sequence of fields that must
              match for a given atom. The first part specifies a residue (or group  of  residues)
              and  an  optional  second part specifies the atoms within those residues. The first
              part consists of a residue name, optionally followed by  a  residue  number  and/or
              chain identifier.

              The  second  part consists of a period character followed by an atom name.  An atom
              name may be up to four alphabetic or numeric  characters.   An  optional  semicolon
              followed  by  an  alternate  conformation  identifier may be appended.  An optional
              slash followed by a model number may also be appended.

              An asterisk may be used as a wild card for a whole field and a question mark  as  a
              single character wildcard.

       Comparison Operators
              Parts  of  a  molecule  may  also  be  distinguished using equality, inequality and
              ordering operators on their properties. The format of such comparison expression is
              a property name, followed by a comparison operator and then an integer value.

              The  atom  properties  that  may  be  used in RasMol are atomno for the atom serial
              number, elemno for the atom's  atomic  number  (element),  resno  for  the  residue
              number, radius for the spacefill radius in RasMol units (or zero if not represented
              as a sphere) and temperature for the PDB isotropic temperature value.

              The equality operator is denoted either "=" or "==".  The  inequality  operator  as
              either  "<>", "!=" or "/=".  The ordering operators are "<" for less than, "<=" for
              less than or equal to, ">" for greater than, and ">" for greater than or equal to.

       Within Expressions
              A RasMol within expression allows atoms  to  be  selected  on  their  proximity  to
              another set of atoms. A within expression takes two parameters separated by a comma
              and surrounded by parentheses. The first argument is an integer  value  called  the
              "cut-off"  distance  of the within expression and the second argument is any  valid
              atom expression. The cut-off distance is expressed in either integer  RasMol  units
              or  Angstroms  containing a decimal point.  An atom is selected if it is within the
              cut-off distance of any of the atoms defined by the second  argument.  This  allows
              complex expressions to be constructed containing nested within expressions.

              For  example, the command select within(3.2,backbone) selects any atom within a 3.2
              Angstrom radius of any  atom  in  a  protein  or  nucleic  acid  backbone.   Within
              expressions are particularly useful for selecting the atoms around an active site.

       Predefined Sets
              RasMol atom expressions may contain predefined sets. These sets are single keywords
              that represent portions of a molecule  of  interest.   Predefined  sets  are  often
              abbreviations  of  primitive atom expressions.  In some cases the use of predefined
              sets allows  selection  of  areas  of  a  molecule  that  could  not  otherwise  be
              distinguished.   A  list  of  the  currently  predefined  sets  is given below.  In
              addition to the sets listed here, RasMol  also  treats  element  names  (and  their
              plurals)  as  predefined  sets  containing all atoms of that element type, i.e. the
              command select oxygen is equivalent to the command select elemno=8.

Predefined Sets

       AT Set This set  contains  the  atoms  in  the  complementary  nucleotides  adenosine  and
              thymidine (A and T, respectively). All nucleotides are classified as either the set
              at or the set cg This set is equivalent to the RasMol  atom  expressions  a,t,  and
              nucleic and not cg.

       Acidic Set
              The set of acidic amino acids.  These are the residue types Asp and Glu.  All amino
              acids are classified as either acidic, basic or neutral.  This set is equivalent to
              the RasMol atom expressions asp, glu and amino and not (basic or neutral).

       Acyclic Set
              The set of atoms in amino acids not containing a cycle or ring. All amino acids are
              classified as either cyclic or acyclic.  This set is equivalent to the RasMol  atom
              expression amino and not cyclic.

       Aliphatic Set
              This  set  contains the aliphatic amino acids.  These are the amino acids Ala, Gly,
              Ile, Leu and Val.  This set is equivalent to the RasMol atom expression  ala,  gly,
              ile, leu, val.

       Alpha Set
              The  set  of  alpha  carbons  in  the  protein  molecule. This set is approximately
              equivalent to the RasMol atom expression *.CA.  This command should not be confused
              with  the  predefined  set helix which contains the atoms in the amino acids of the
              protein's alpha helices.

       Amino Set
              This set contains all the atoms contained in amino acid residues.  This  is  useful
              for distinguishing the protein from the nucleic acid and heterogeneous atoms in the
              current molecule database.

       Aromatic Set
              The set of atoms in amino acids containing aromatic rings.   These  are  the  amino
              acids  His,  Phe,  Trp and Tyr.  Because they contain aromatic rings all members of
              this set are member of the predefined set cyclic.  This set is  equivalent  to  the
              RasMol atom expressions his, phe, trp, tyr and cyclic and not pro.

       Backbone Set
              This  set contains the four atoms of each amino acid that form the polypeptide N-C-
              C-O backbone of proteins, and the atoms of the sugar phosphate backbone of  nucleic
              acids.   Use  the RasMol predefined sets protein and nucleic to distinguish between
              the two forms of backbone.  Atoms in nucleic acids and proteins are either backbone
              or sidechain.  This set is equivalent to the RasMol expression (protein or nucleic)
              and not sidechain.

              The predefined set mainchain is synonymous with the set backbone.

       Basic Set
              The set of basic amino acids.  These are the residue types Arg, His and  Lys.   All
              amino  acids  are  classified  as  either  acidic,  basic  or neutral.  This set is
              equivalent to the RasMol atom expressions arg, his, lys and amino and  not  (acidic
              or neutral).

       Bonded Set
              This  set contain all the atoms in the current molecule database that are bonded to
              at least one other atom.

       Buried Set
              This set contains the atoms in those amino acids that tend (prefer)  to  be  buried
              inside  protein,  away  from contact with solvent molecules. This set refers to the
              amino acids preference and not the actual solvent  accessibility  for  the  current
              protein.   All amino acids are classified as either surface or buried.  This set is
              equivalent to the RasMol atom expression amino and not surface.

       CG Set This set contains the atoms in the complementary nucleotides cytidine and guanosine
              (C and G, respectively). All nucleotides are classified as either the set at or the
              set cg This set is equivalent to the RasMol atom expressions c,g  and  nucleic  and
              not at.

       Charged Set
              This  set  contains  the  charged  amino  acids. These are the amino acids that are
              either acidic or basic.  Amino acids are classified  as  being  either  charged  or
              neutral.  This set is equivalent to the RasMol atom expressions acidic or basic and
              amino and not neutral.

       Cyclic Set
              The set of atoms in amino acids containing a cycle or rings.  All amino  acids  are
              classified  as either cyclic or acyclic.  This set consists of the amino acids His,
              Phe, Pro, Trp and Tyr.  The members of the predefined set aromatic are  members  of
              this  set.   The  only  cyclic but non-aromatic amino acid is proline.  This set is
              equivalent to the RasMol atom expressions his, phe, pro, trp, tyr and  aromatic  or
              pro and amino and not acyclic.

       Cystine Set
              This  set  contains  the  atoms of cysteine residues that form part of a disulphide
              bridge, i.e. half cystines. RasMol automatically determines disulphide bridges,  if
              neither  the  predefined  set cystine nor the RasMol ssbonds command have been used
              since the molecule was loaded. The set of free cysteines may  be  determined  using
              the RasMol atom expression cys and not cystine.

       Helix Set
              This  set  contains all atoms that form part of a protein alpha helix as determined
              by either the PDB file author or Kabsch and Sander's DSSP  algorithm.  By  default,
              RasMol  uses  the  secondary  structure  determination  given in the PDB file if it
              exists.  Otherwise, it uses the DSSP algorithm as  used  by  the  RasMol  structure
              command.

              This  predefined  set  should  not  be confused with the predefined set alpha which
              contains the alpha carbon atoms of a protein.

       Hetero Set
              This set contains all the heterogeneous atoms in the molecule. These are the  atoms
              described  by  HETATM  entries  in  the  PDB  file.  These typically contain water,
              cofactors and other solvents and ligands. All hetero atoms are classified as either
              ligand  or  solvent atoms. These heterogeneous solvent atoms are further classified
              as either water or ions.

       Hydrogen Set
              This predefined set contains all the hydrogen, deuterium and tritium atoms  of  the
              current  molecule.  This predefined set is equivalent to the RasMol atom expression
              elemno=1.

       Hydrophobic Set
              This set contains all the hydrophobic amino acids.  These are the amino acids  Ala,
              Leu,  Val,  Ile,  Pro,  Phe, Met and Trp.  All amino acids are classified as either
              hydrophobic or polar.  This set is equivalent to the RasMol atom  expressions  ala,
              leu, val, ile, pro, phe, met, trp and amino and not polar.

       Ions Set
              This  set contains all the heterogeneous phosphate and sulphate ions in the current
              molecule data file. A large number of these  ions  are  sometimes  associated  with
              protein  and  nucleic  acid  structures  determined by X-ray crystallography. These
              atoms tend to clutter an image. All hetero atoms are classified as either ligand or
              solvent atoms. All solvent atoms are classified as either water or ions.

       Large Set
              All  amino  acids  are  classified  as  either small, medium or large.  This set is
              equivalent to the RasMol atom expression amino and not (small or medium).

       Ligand Set
              This set contains all the heterogeneous  cofactor  and  ligand  moieties  that  are
              contained  in the current molecule data file.  This set is defined to be all hetero
              atoms that are not solvent atoms. Hence this set is equivalent to the  RasMol  atom
              expression hetero and not solvent.

       Medium Set
              All  amino  acids  are  classified  as  either small, medium or large.  This set is
              equivalent to the RasMol atom expression amino and not (large or small).

       Neutral Set
              The set of neutral amino acids.  All amino acids are classified as  either  acidic,
              basic  or  neutral.  This set is equivalent to the RasMol atom expression amino and
              not (acidic or basic).

       Nucleic Set
              The set of all atoms in nucleic acids, which consists of the four nucleotide  bases
              adenosine,  cytidine,  guanosine  and  thymidine (A, C, G and T, respectively). All
              neucleotides are classified as either purine or pyrimidine.  This set is equivalent
              to  the  RasMol atom expressions a,c,g,t and purine or pyrimidine.  The symbols for
              RNA nucleotides (U, +U, I, 1MA, 5MC, OMC, 1MG, 2MG, M2G, 7MG, OMG,  YG,  H2U,  5MU,
              and PSU) are also recognized as members of this set.

       Polar Set
              This  set contains the polar amino acids.  All amino acids are classified as either
              hydrophobic or polar.  This set is equivalent to the RasMol atom  expression  amino
              and not hydrophobic.

       Protein Set
              The  set of all atoms in proteins. This consists of the RasMol predefined set amino
              and common post-translation modifications.

       Purine Set
              The set of purine nucleotides.  These are the bases adenosine and guanosine (A  and
              G,  respectively).  All nucleotides are either purines or pyrimidines.  This set is
              equivalent to the RasMol atom expressions a,g and nucleic and not pyrimidine.

       Pyrimidine Set
              The set of pyrimidine nucleotides.  These are the bases cytidine and  thymidine  (C
              and T, respectively).  All nucleotides are either purines or pyrimidines.  This set
              is equivalent to the RasMol atom expressions c,t and nucleic and not purine.

       Selected Set
              This set contains the set of atoms in the currently selected region. The  currently
              selected  region is defined by the preceding select or restrict command and not the
              atom expression containing the selected keyword.

       Sheet Set
              This set contains all atoms that form part of a protein beta sheet as determined by
              either  the  PDB  file  author  or  Kabsch and Sander's DSSP algorithm. By default,
              RasMol uses the secondary structure determination given  in  the  PDB  file  if  it
              exists.   Otherwise,  it  uses  the  DSSP algorithm as used by the RasMol structure
              command.

       Sidechain Set
              This set contains the functional sidechains of any amino acids and the base of each
              nucleotide.  These  are  the  atoms not part of the polypeptide N-C-C-O backbone of
              proteins or the  sugar  phosphate  backbone  of  nucleic  acids.   Use  the  RasMol
              predefined  sets  protein  and  nucleic  to  distinguish  between  the two forms of
              sidechain.  Atoms in nucleic acids and proteins are either backbone  or  sidechain.
              This  set  is  equivalent  to  the  RasMol  expression (protein or nucleic) and not
              backbone.

       Small Set
              All amino acids are classified as either small,  medium  or  large.   This  set  is
              equivalent to the RasMol atom expression amino and not (medium or large).

       Solvent Set
              This set contains the solvent atoms in the molecule coordinate file.  These are the
              heterogeneous water molecules, phosphate and sulphate ions. All  hetero  atoms  are
              classified  as  either ligand or solvent atoms. All solvent atoms are classified as
              either water or ions.  This set is equivalent to the RasMol atom expressions hetero
              and not ligand and water or ions.

       Surface Set
              This  set  contains  the atoms in those amino acids that tend (prefer) to be on the
              surface of proteins, in contact with solvent molecules.  This  set  refers  to  the
              amino  acids  preference  and  not the actual solvent accessibility for the current
              protein.  All amino acids are classified as either surface or buried.  This set  is
              equivalent to the RasMol atom expression amino and not buried.

       Turn Set
              This  set  contains  all  atoms  that form part of a protein turns as determined by
              either the PDB file author or Kabsch  and  Sander's  DSSP  algorithm.  By  default,
              RasMol  uses  the  secondary  structure  determination  given in the PDB file if it
              exists.  Otherwise, it uses the DSSP algorithm as  used  by  the  RasMol  structure
              command.

       Water Set
              This  set contains all the heterogeneous water molecules in the current database. A
              large number of water molecules are sometimes associated with protein  and  nucleic
              acid structures determined by X-ray crystallography. These atoms tend to clutter an
              image.  All hetero atoms are classified as either  ligand  or  solvent  atoms.  The
              solvent atoms are further classified as either water or ions.

       Set Summary
              The table below summarises RasMol's classification of the common amino acids.

COLOUR SCHEMES

       The  RasMol  colour  command  allows  different  objects  (such as atoms, bonds and ribbon
       segments) to be given a specified  colour.  Typically  this  colour  is  either  a  RasMol
       predefined  colour  name  or  an RGB triple. Additionally RasMol also supports alt, amino,
       chain, charge, cpk, group, model, shapely, structure, temperature or user  colour  schemes
       for  atoms,  and  hbond  type colour scheme for hydrogen bonds and electrostatic potential
       colour scheme for dot surfaces.  The 24 currently predefined colour names are Black, Blue,
       BlueTint,  Brown, Cyan, Gold, Grey, Green, GreenBlue, GreenTint, HotPink, Magenta, Orange,
       Pink, PinkTint, Purple, Red, RedOrange,  SeaGreen,  SkyBlue,  Violet,  White,  Yellow  and
       YellowTint

       If  you  frequently  wish to use a colour not predefined, you can write a one-line script.
       For example, if you make the file  grey.col  containing  the  line,  colour  [180,180,180]
       #grey, then the command script grey.col colours the currently selected atom set grey.

       Alt Colours
              The  RasMol  alt  (Alternate Conformer) colour scheme codes the base structure with
              one colour and applies a limited number of colours to each alternate conformer.  In
              a  RasMol  built  for  8-bit  colour  systems,  4 colours are allowed for alternate
              conformers. Otherwise, 8 colours are available.

       Amino Colours
              The RasMol amino colour scheme colours amino acids according to  traditional  amino
              acid  properties. The purpose of colouring is to identify amino acids in an unusual
              or surprising environment. The outer parts of a protein that are polar are  visible
              (bright)  colours  and  non-polar  residues  darker.  Most  colours are hallowed by
              tradition. This colour scheme is similar to the shapely scheme.

       Chain Colours
              The RasMol chain colour scheme assigns each macromolecular chain a  unique  colour.
              This  colour  scheme  is  particularly  useful  for  distinguishing  the  parts  of
              multimeric structure or the individual 'strands' of a  DNA  chain.   Chain  can  be
              selected from the RasMol Colours menu.

       Charge Colours
              The  RasMol  charge  colour  scheme  colour codes each atom according to the charge
              value stored in the input file (or beta factor field of PDB files). High values are
              coloured  in  blue  (positive)  and lower values coloured in red (negative). Rather
              than use a fixed scale this scheme determines the maximum and minimum values of the
              charge/temperature  field  and  interpolates from red to blue appropriately. Hence,
              green cannot be assumed to be 'no net charge' charge.

              The difference between the charge and temperature colour schemes is that increasing
              temperature  values  proceed  from blue to red, whereas increasing charge values go
              from red to blue.

              If the charge/temperature field stores reasonable values it is possible to use  the
              RasMol colour dots potential command to colour code a dot surface (generated by the
              dots command) by electrostatic potential.

       CPK Colours
              The RasMol cpk colour scheme is based upon  the  colours  of  the  popular  plastic
              spacefilling  models  which  were developed by Corey, Pauling and later improved by
              Kultun. This colour scheme colours 'atom' objects by the atom (element) type.  This
              is the scheme conventionally used by chemists.  The assignment of the most commonly
              used element types to colours is given below.

       Group Colours
              The RasMol group colour scheme  colour  codes  residues  by  their  position  in  a
              macromolecular  chain.  Each  chain is drawn as a smooth spectrum from blue through
              green, yellow and orange to red. Hence the N terminus of proteins and  5'  terminus
              of nucleic acids are coloured red and the C terminus of proteins and 3' terminus of
              nucleic acids are drawn in blue. If a chain has a  large  number  of  heterogeneous
              molecules  associated  with  it,  the  macromolecule  may  not be drawn in the full
              'range' of the spectrum.  Group can be selected from the RasMol Colours menu.

              If a chain has a large number of heterogeneous molecules associated  with  it,  the
              macromolecule  may  not  be  drawn  in  the full range of the spectrum. When RasMol
              performs group colouring it decides the range of colours it uses from  the  residue
              numbering  given  in  the PDB file. Hence the lowest residue number is displayed in
              blue and the highest residue number is displayed as red. Unfortunately,  if  a  PDB
              file  contains  a large number of heteroatoms, such as water molecules, that occupy
              the high residue numbers, the protein is displayed in the  blue-green  end  of  the
              spectrum  and  the waters in the yellow-red end of the spectrum. This is aggravated
              by there typically being many more water molecules than amino  acid  residues.  The
              solution  to  this problem is to use the command set hetero off before applying the
              group colour scheme. This can also be achieved by  toggling  Hetero  Atoms  on  the
              Options  menu  before  selecting  Group  on the Colour menu. This command instructs
              RasMol to only use non-hetero residues in the group colour scaling.

       NMR Model Colours
              The RasMol model colour scheme codes each NMR model with a  distinct  colour.   The
              NMR model number is taken as a numeric value.  High values are coloured in blue and
              lower values coloured in red. Rather than use a fixed scale this scheme  determines
              the  maximum  value  of  the  NMR  model  number  and interpolates from red to blue
              appropriately.

       Shapely Colours
              The RasMol shapely colour scheme colour codes residues by amino acid property. This
              scheme is based upon Bob Fletterick's "Shapely Models". Each amino acid and nucleic
              acid residue is given a unique colour. The shapely colour scheme is used  by  David
              Bacon's Raster3D program. This colour scheme is similar to the amino colour scheme.

       Structure Colours
              The  RasMol  structure  colour  scheme  colours  the  molecule by protein secondary
              structure.  Alpha helices  are  coloured  magenta,  [240,0,128],  beta  sheets  are
              coloured  yellow,  [255,255,0],  turns are coloured pale blue, [96,128,255] and all
              other residues are coloured white. The secondary structure is either read from  the
              PDB  file (HELIX, SHEET and TURN records), if available, or determined using Kabsch
              and Sander's DSSP algorithm. The RasMol structure command  may  be  used  to  force
              DSSP's structure assignment to be used.

       Temperature Colours
              The  RasMol  temperature  colour  scheme  colour  codes  each atom according to the
              anisotropic temperature (beta) value stored in the PDB file. Typically this gives a
              measure  of  the  mobility/uncertainty  of a given atom's position. High values are
              coloured in warmer (red) colours and lower values in colder  (blue)  colours.  This
              feature  is often used to associate a "scale" value [such as amino acid variability
              in viral  mutants]  with  each  atom  in  a  PDB  file,  and  colour  the  molecule
              appropriately.

              The difference between the temperature and charge colour schemes is that increasing
              temperature values proceed from blue to red, whereas increasing  charge  values  go
              from red to blue.

       User Colours
              The  RasMol user colour scheme allows RasMol to use the colour scheme stored in the
              PDB file. The colours for each atom are stored in COLO records placed  in  the  PDB
              data file. This convention was introduced by David Bacon's Raster3D program.

       HBond Type Colours
              The  RasMol type colour scheme applies only to hydrogen bonds, hence is used in the
              command colour hbonds type.  This scheme colour codes each hydrogen bond  according
              to  the  distance  along  a protein chain between hydrogen bond donor and acceptor.
              This schematic representation was introduced by Belhadj-Mostefa  and  Milner-White.
              This  representation  gives a good insight into protein secondary structure (hbonds
              forming alpha helices appear red, those forming  sheets  appear  yellow  and  those
              forming turns appear magenta).

       Potential Colours
              The  RasMol  potential colour scheme applies only to dot surfaces, hence is used in
              the command colour dots potential.  This scheme colours  each  currently  displayed
              dot  by  the  electrostatic  potential  at  that  point in space. This potential is
              calculated using Coulomb's law taking the temperature/charge  field  of  the  input
              file  to  be  the  charge assocated with that atom. This is the same interpretation
              used by the colour charge command. Like the charge colour  scheme  low  values  are
              blue/white and high values are red.

       Amino Acid Codes
              The  following  table lists the names, single letter and three letter codes of each
              of the amino acids.

       Booleans
              A boolean parameter is a truth value. Valid boolean values are 'true' and  'false',
              and  their  synonyms 'on' and 'off'. Boolean parameters are commonly used by RasMol
              to either enable or disable a representation or option.

FILE FORMATS

       Protein Data Bank Files

       If you do not have the PDB documentation, you may find the following summary  of  the  PDB
       file  format  useful.  The  Protein  Data  Bank  is a computer-based archival database for
       macromolecular structures.  The database was established in 1971  by  Brookhaven  National
       Laboratory,  Upton,  New York, as a public domain repository for resolved crystallographic
       structures. The Bank uses a uniform format to store atomic coordinates  and  partial  bond
       connectivities  as  derived  from crystallographic studies.  In 1999 the Protein Data Bank
       moved to the Research Collaboratory for Structural Biology.

       PDB file entries consist of records of 80 characters each. Using the punched card analogy,
       columns  1  to  6  contain  a record-type identifier, the columns 7 to 70 contain data. In
       older entries, columns 71 to 80 are normally blank, but may contain  sequence  information
       added  by  library management programs.  In new entries conforming to the 1996 PDB format,
       there is other information in those columns. The  first  four  characters  of  the  record
       identifier  are sufficient to identify the type of record uniquely, and the syntax of each
       record is independent  of  the  order  of  records  within  any  entry  for  a  particular
       macromolecule.

       The  only  record  types that are of major interest to the RasMol program are the ATOM and
       HETATM records which describe the position  of  each  atom.  ATOM/HETATM  records  contain
       standard   atom   names  and  residue  abbreviations,  along  with  sequence  identifiers,
       coordinates in Angstrom units, occupancies and thermal motion factors. The  exact  details
       are  given  below  as  a  FORTRAN format statement.  The "fmt" column indicates use of the
       field in all PDB formats, in the 1992 and  earlier  formats  or  in  the  1996  and  later
       formats.

       Residues  occur in order starting from the N-terminal residue for proteins and 5'-terminus
       for nucleic acids. If the residue sequence is known, certain atom serial  numbers  may  be
       omitted to allow for future insertion of any missing atoms. Within each residue, atoms are
       ordered in a standard manner, starting  with  the  backbone  (N-C-C-O  for  proteins)  and
       proceeding in increasing remoteness from the alpha carbon, along the side chain.

       HETATM   records  are  used  to  define  post-translational  modifications  and  cofactors
       associated with the main molecule. TER records are  interpreted  as  breaks  in  the  main
       molecule's backbone.

       If  present,  RasMol  also  inspects  HEADER,  COMPND, HELIX, SHEET, TURN, CONECT, CRYST1,
       SCALE, MODEL, ENDMDL, EXPDTA and END records. Information such as the name, database code,
       revision  date  and  classification  of  the molecule are extracted from HEADER and COMPND
       records, initial secondary structure assignments are taken  from  HELIX,  SHEET  and  TURN
       records, and the end of the file may be indicated by an END record.

       RasMol Interpretation of PDB fields
              Atoms  located  at  9999.000,  9999.000,  9999.000 are assumed to be Insight pseudo
              atoms and are ignored by RasMol. Atom names beginning ' Q' are also assumed  to  be
              pseudo atoms or position markers.

              When a data file contains an NMR structure, multiple conformations may be placed in
              a single PDB file delimited by pairs of MODEL and ENDMDL records.  RasMol  displays
              all the NMR models contained in the file.

              Residue  names "CSH", "CYH" and "CSM" are considered pseudonyms for cysteine "CYS".
              Residue names "WAT", "H20", "SOL" and "TIP" are  considered  pseudonyms  for  water
              "HOH". The residue name "D20" is consider heavy water "DOD". The residue name "SUL"
              is considered a sulphate ion "SO4". The residue name "CPR" is considered to be cis-
              proline  and  is  translated  as  "PRO".  The  residue  name  "TRY" is considered a
              pseudonym for tryptophan "TRP".

              RasMol uses the HETATM fields to define the sets hetero, water, solvent and ligand.
              Any  group  with  the name "HOH", "DOD", "SO4" or "PO4" (or aliased to one of these
              names by the preceding rules) is considered a  solvent  and  is  considered  to  be
              defined by a HETATM field.

              RasMol only respects CONECT connectivity records in PDB files containing fewer than
              256 atoms. This is explained in more detail in the section on determining  molecule
              connectivity.  CONECT  records that define a bond more than once are interpreted as
              specifying the bond order of that bond, i.e. a bond specified  twice  is  a  double
              bond  and  a  bond specified three (or more) times is a triple bond.  This is not a
              standard PDB feature.

       PDB Colour Scheme Specification
              RasMol also accepts the supplementary COLO record  type  in  the  PDB  files.  This
              record  format  was introduced by David Bacon's Raster3D program for specifying the
              colour scheme to be used  when  rendering  the  molecule.  This  extension  is  not
              currently  supported  by the PDB. The COLO record has the same basic record type as
              the ATOM and HETATM records described above.

              Colours are assigned to atoms using a matching process. The Mask field is  used  in
              the  matching process as follows. First RasMol reads in and remembers all the ATOM,
              HETATM and COLO records in input  order.  When  the  user-defined  ('User')  colour
              scheme is selected, RasMol goes through each remembered ATOM/HETATM record in turn,
              and searches for a COLO record that matches in all of columns  7  through  30.  The
              first such COLO record to be found determines the colour and radius of the atom.

              Note that the Red, Green and Blue components are in the same positions as the X, Y,
              and Z components of an ATOM or HETA record, and the van der Waals  radius  goes  in
              the  place  of the Occupancy. The Red, Green and Blue components must all be in the
              range 0 to 1.

              In order that one COLO record can provide colour and radius specifications for more
              than  one  atom (e.g. based on residue, atom type, or any other criterion for which
              labels can be given somewhere in columns 7 through 30), a  'don't-care'  character,
              the  hash  mark "#" (number or sharp sign) is used. This character, when found in a
              COLO record, matches any character in the corresponding  column  in  a  ATOM/HETATM
              record.  All  other  characters  must  match identically to count as a match. As an
              extension to the specification, any atom that fails  to  match  a  COLO  record  is
              displayed in white.

       Multiple NMR Models
              RasMol loads all of the NMR models from a PDB file no matter which command is used:
              load pdb <filename> or load nmrpdb <filename>

              Once multiple NMR conformations have been loaded they may be manipulated  with  the
              atom  expression extensions described in Primitive Expressions.  In particular, the
              command restrict */1 will restrict the display to the first model only.

       CIF and mmCIF Format Files
              CIF is the IUCr standard for presentation of small molecules and mmCIF is  intended
              as   the   replacement   for   the  fixed-field  PDB  format  for  presentation  of
              macromolecular structures. RasMol can accept data sets in either format.

              There are many useful sites on the World  Wide  Web  where  information  tools  and
              software  related  to  CIF,  mmCIF and the PDB can be found. The following are good
              starting points for exploration:

              The International Union of Crystallography  (IUCr)  provides  access  to  software,
              dictionaries,  policy  statements  and  documentation relating to CIF and mmCIF at:
              IUCr, Chester, England (www.iucr.org/iucr-top/cif/) with many mirror sites.

              The Nucleic Acid Database Project provides access  to  its  entries,  software  and
              documentation,  with  an  mmCIF  page  giving  access  to  the dictionary and mmCIF
              software     tools     at     Rutgers     University,     New      Jersey,      USA
              (http://ndbserver.rutgers.edu/NDB/mmcif) with many mirror sites.

              This  version  of  RasMol restricts CIF or mmCIF tag values to essentially the same
              conventions as are used for the fixed-field PDB format. Thus chain identifiers  and
              alternate  conformation  identifiers  are limited to a single character, atom names
              are limited to 4 characters, etc. RasMol interprets the  following  CIF  and  mmCIF
              tags:  A  search  is  made  through multiple data blocks for the desired tags, so a
              single dataset may be composed from multiple data blocks, but  multiple  data  sets
              may not be stacked in the same file.

MACHINE-SPECIFIC SUPPORT

       In  the  following  sections,  support  for Monochrome X-Windows, Tcl/Tk IPC, UNIX sockets
       based IPC, Compiling RasWin with Borland and MetroWerks are described.

       Monochrome X-Windows Support
              RasMol supports the many monochrome UNIX workstations typically found in  academia,
              such  as  low-end  SUN  workstations and NCD X-terminals. The X11 version of RasMol
              (when compiled in 8 bit mode) now detects black and white  X-Windows  displays  and
              enables  dithering  automatically.  The  use  of run-time error diffusion dithering
              means that all display modes of RasMol are available when in monochrome  mode.  For
              best  results,  users  should experiment with the set ambient command to ensure the
              maximum contrast in resulting images.

       Tcl/Tk IPC support
              Version 4 of Tk graphics library changed the protocol used to  communicate  between
              Tk  applications.  RasMol  version  2.6 was modified such that it could communicate
              with both this new protocol and the previous version 3 protocol supported by RasMol
              v2.5.  Although  Tcl/Tk  3.x  applications  may  only  communicate  with  other 3.x
              applications and Tcl/Tk 4.x applications with other 4.x applications, these changes
              allow  RasMol  to  communicate  between  processes with both protocols (potentially
              concurrently).

       UNIX sockets based IPC
              The UNIX implementation of  RasMol  supports  BSD-style  socket  communication.  An
              identical  socket  mechanism  is  also being developed for VMS, Apple Macintosh and
              Microsoft Windows systems.  This  should  allow  RasMol  to  interactively  display
              results  of  a  computation on a remote host. The current protocol acts as a TCP/IP
              server on port 21069 that executes command lines until either the command  exit  or
              the  command  quit  is  typed. The command exit from the RasMol server, the command
              quit both disconnects the current session and terminates RasMol. This functionality
              may be tested using the UNIX command telnet <hostname> 21069.

       Compiling RasWin with Borland and MetroWerks
              A number of changes were made to the source code in the transition from version 2.5
              to 2.6 to allow the Microsoft Windows  version  of  RasMol  to  compile  using  the
              Borland  C/C++  compiler. These fixes include name changes for the standard library
              and special code to avoid a bug in _fmemset.  Additional changes were made  in  the
              transition from 2.6 to 2.7 to allow compilation with the MetroWerks compilers.

BIBLIOGRAPHY

       Molecular Graphics

       [1]  Nelson  Max,  "Computer Representation of Molecular Surfaces", IEEE Computer Graphics
       and Applications, pp.21-29, August 1983.

       [2] Arthur M. Lesk, "Protein Architecture: A Practical Approach",  IRL  Press  Publishers,
       1991.

       Molecular Graphics Programs

       [3]  Per J. Kraulis, "MOLSCRIPT: A Program to Produce both Detailed and Schematic Plots of
       Protein Structures", Journal of Applied Crystallography, Vol.24, pp.946-950, 1991.

       [4] David Bacon and Wayne F. Anderson,  "A  Fast  Algorithm  for  Rendering  Space-Filling
       Molecule Pictures", Journal of Molecular Graphics, Vol.6, No.4, pp.219-220, December 1988.

       [5]  David  C.  Richardson  and  Jane  S. Richardson, "The Kinemage: A tool for Scientific
       Communication", Protein Science, Vol.1, No.1,pp.3-9, January 1992.

       [6] Mike Carson, "RIBBONS 2.0", Journal of Applied  Crystallography,  Vol.24,  pp.958-961,
       1991.

       [7]  Conrad  C.  Huang,  Eric  F.  Pettersen,  Teri E. Klein, Thomas E.  Ferrin and Robert
       Langridge, "Conic: A Fast Renderer for Space-Filling Molecules with Shadows",  Journal  of
       Molecular Graphics, Vol.9, No.4, pp.230-236, December 1991.

       Molecular Biology Algorithms

       [8]  Wolfgang  Kabsch  and  Christian  Sander, "Dictionary of Protein Secondary Structure:
       Pattern Recognition of Hydrogen-Bonded and  Geometrical  Features",  Biopolymers,  Vol.22,
       pp.2577-2637, 1983.

       [9]  Michael  L.  Connolly,  "Solvent-Accessible  Surfaces of Proteins and Nucleic Acids",
       Science, Vol.221, No.4612, pp.709-713, August 1983.

       [10] Khaled Belhadj-Mostefa, Ron Poet and E. James  Milner-White,  "Displaying  Inter-Main
       Chain  Hydrogen  Bond  Patterns  in Proteins", Journal of Molecular Graphics, Vol.9, No.3,
       pp.194-197, September 1991.

       [11] Mike Carson, "Ribbon Models of Macromolecules", Journal of Molecular Graphics, Vol.5,
       No.2, pp.103-106, June 1987.

       [12]  Mike  Carson and Charles E. Bugg, "Algorithm for Ribbon Models of Proteins", Journal
       of Molecular Graphics, Vol.4, No.2, pp.121-122, June 1986.

       [13] H. Iijima, J. B. Dunbar Jr. and G. Marshall, "Calibration of Effective van der  Waals
       Atomic  Contact  Radii  for  Proteins  and  Peptides",  Proteins: Structure, Functions and
       Genetics, Vol.2, pp.330-339,1987.

       Graphics Algorithms

       [14] J. Foley, A. van Dam, S. Feiner and J. Hughes,  "Computer  Graphics:  Principles  and
       Practice", 2nd Edition, Addison Wesley Publishers, 1990.

       [15] J. Cleary and G. Wyvill, "Analysis of an Algorithm for Fast Ray Tracing using Uniform
       Space Subdivision", The Visual Computer, Vol.4, pp.65-83, 1988.

       [16]  Thomas  Porter,"Spherical  Shading",  Computer  Graphics   Vol.12,   ACM   SIGGRAPH,
       pp.282-285, 1978.

       [17] Jean-Michel Cense, "Exact Visibility Calculation for Space-Filling Molecular Models",
       Journal of Molecular Graphics, Vol.9, No.3, pp.191-193, September 1991.

       [18]  Chris  Schafmeister,  "Fast  Algorithm  for  Generating  CPK  Images   on   Graphics
       Workstations", Journal of Molecular Graphics, Vol.8, No.4, pp.201-206, December 1990.

       [19]  Bruce  A.  Johnson,  "MSURF:  A  Rapid and General Program for the Representation of
       Molecular Surfaces", Journal of Molecular Graphics,  Vol.5,  No.3,  pp.167-169,  September
       1987.

       File Formats

       [20]  Frances  C. Bernstein et al., "The Protein Data Bank: A Computer-Based Archival File
       for Macromolecular Structures", Journal of Molecular Biology, Vol.112, pp.535-542, 1977.

       [21] Arthur Dalby, James G. Nourse, W. Douglas Hounshell, Ann K. I.   Gushurst,  David  L.
       Grier,  Burton  A.  Leland  and John Laufer, "Description of Several Chemical File Formats
       Used by Computer Programs Developed at Molecular  Design  Limited",  Journal  of  Chemical
       Information and Computer Sciences, Vol.32, No.3, pp.244-255, 1992.

       [22]   Adobe   Systems   Inc.,  "PostScript  Language  Reference  Manual",  Addison-Wesley
       Publishers, Reading, Mass., 1985.

       [23] Philip E. Bourne  et  al.,  "The  Macromolecular  Crystallographic  Information  File
       (mmCIF)", Meth. Enzymol. (1997) 277, 571-590.

       [24]  Sydney  R.  Hall,  "The  STAR  File:  a  New Format for Electronic Data Transfer and
       Archiving", Journal of Chemical Information and Computer Sciences, Vol. 31, 326-333, 1991.

SEE ALSO

       The RasMol User Manual!

AUTHOR

       1992-1998 by Roger Sayle (rasmol@ggr.co.uk)

                                            July 2009                                   RASMOL(1)