The original RasMol manual was created by Roger Sayle. In July 1996, Dr. Margaret Wong of the Chemistry Department, Swinburne University of Technology, Australia, made extensive revisions to the RasMol 2.5 manual to accurately reflect the operation of RasMol 2.6. Eric Martz of the University of Massachusetts made further revisions. In May 1997, William McClure of Carnegie Mellon University reorganized the HTML version of the manual into multiple sections which could be downloaded quickly and added use of frames. Portions of the 2.7.1 version of the RasMol manual were derived with permission from William McClure's version using Roger Sayle's rasmol.doc for version 2.6.4 as the primary source. Changes have been made in August 2000 for RasMol version 2.7.2, January 2001 for RasMol version 2.7.1.1 and April 2001 for RasMol version 2.7.2.1.

Translations

Thanks to the efforts of José Miguel Fernández Fernández (Departamento de Bioquímica y Biología Molecular. Universidad de Granada. España (jmfernan@ugr.es)) a translation of the Manual for Rasmol version 2.7.1 into Spanish is now available. La traducción española del manual de la versión de la Dra. Wong revisada por Eric Martz fue realizada por Isabel Serván Martínez y José Miguel Fernández Fernández. La actual traducción del Manual de RasMol 2.7.1 ha sido realizada usando como base la anterior de RasMol 2.6 por  José Miguel Fernández Fernández.

Thanks to translations by Fernando Gabriel Ranea in late 2000 and early 2001, RasMol is now capable of rendering most menu items and messages in Spanish. Jean-Pierre Demailly provided French translations of menus and messages in January 2001. Giuseppe Martini and Giovanni Paolella with contributions by A. Davassi, M. Masullo and C. Liotto provided Italian translations of menus and messages in March 2001.

THIS IS A PRELIMINARY RELEASE INVOLVING EXTENSIVE MODIFICATIONS
***** USE WITH CAUTION ******

IMPORTANT

This version is based directly on RasMol 2.7.1, on RasMol version 2.6_CIF.2, on RasMol version 2.6x1, on RasMol version 2.6.4, and RasMol 2.5-ucb and 2.6-ucb. Please read the file NOTICE for important notices which apply to this package. If you are not going to make changes to RasMol, you are not only permitted to freely make copies and distribute them, you are encouraged to do so, 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 the documentation; and
• 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 providing a warranty of any kind.

If you would like to use major pieces of RasMol in some other program, make modifications to RasMol, or in some other way make what a lawyer would call a "derived work", you are not only permitted to do so, you are encouraged to do so. 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.

Table of Contents

1. Notices
2. Introduction
3. General Operation
   • Running RasMol Under UNIX or VMS
   • Running RasMol Under Microsoft Windows
   • Running RasMol on the Apple Macintosh/PPC
   • RasMol's Window
   • Mouse Controls
   • Scroll Bars
   • Picking
   • Dials Box
   • Command Line Interface
   • Dimensions within RasMol
   • Start-up Initialisation Files
   • Inter-Process Communication (IPC)
4. Command Reference

   Backbone	Background	Bond	Cartoon	Centre	Clipboard	Colour	Connect
   CPK	Define	Depth	Dots	Echo	English	Exit	French
   HBonds	Help	Italian	Label	Load	Molecule	Monitor	Pause
   Print	Quit	Refresh	Renumber	Reset	Restrict	Ribbons	Rotate
   Save	Script	Select	Set	Show	Slab	Source	Spacefill
   Spanish	SSBonds	Star	Stereo	Strands	Structure	Trace	Translate
   UnBond	Wireframe	Write	Zap	Zoom

5. Internal Parameters

   Ambient	Axes	Background	BackFade	BondMode	Bonds	BoundBox	Cartoon
   CisAngle	Display	FontSize	FontStroke	HBonds	Hetero	HourGlass	Hydrogen
   Kinemage	Menus	Monitor	Mouse	Picking	Radius	ShadePower	Shadow
   SlabMode	Solvent	Specular	SpecPower	Stereo	SSBonds	Strands	Transparent
   UnitCell	VectPS	Write

6. Atom Expressions
7. Predefined Sets
8. Colour Schemes
9. File Formats
10. File Machine-Specific Support
11. Bibliography

RasMol Copyright © Roger Sayle 1992-1999
Version 2.6x1 Mods Copyright © Arne Mueller 1998
Versions 2.5-ucb and 2.6-ucb Mods Copyright © UC Regents/ModularCHEM Consortium 1995, 1996
RasTop 1.3 Copyright © Philippe Valadon 2000
Version 2.7.0, 2.7.1, 2.7.1.1, 2.7.2, 2.7.2.1 Mods Copyright © Herbert J. Bernstein 1998-2001

All rights reserved. Use of copyright notice does not imply publication or disclosure. The information supplied in this document is believed to be true but no liability is assumed for its use or for the infringements of the rights of the others resulting from its use. Information in this document is subject to change without notice and does not represent a commitment on the part of the supplier.

This software has been created from several sources. Much of the code is from RasMol 2.6, as created by Roger Sayle.

See: ftp://ftp.dcs.ed.ac.uk/pub/rasmol

The torsion angle code, new POVRAY3 code and other features are derived from the RasMol2.6x1 revisions by Arne Mueller.

See: ftp://nexus.roko.goe.net/pub/rasmol

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.

See: http://mc2.CCHem.Berkeley.EDU/RasMol

The CIF modifications make use of a library based in part on CBFlib by Paul J. Ellis and Herbert J. Bernstein.

See: http://www.bernstein-plus-sons.com/software/CBF

Parts of CBFlib is loosely based on the CIFPARSE software package from the NDB at Rutgers university.

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

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'.

This version is based in large part on 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.

If you are not going to make changes to RasMol, you are not only permitted to freely make copies and distribute them, you are encouraged to do so, 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 the documentation; and

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 providing a warranty of any kind.

If you would like to use major pieces of RasMol in some other program, make modifications to RasMol, or in some other way make what a lawyer would call a "derived work", you are not only permitted to do so, you are encouraged to do so. 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.

The following notice applies to this work as a whole and to the works included within it:

* Creative endeavors depend on the lively exchange of ideas. There are laws and customs which establish rights and responsibilities for authors and the users of what authors create. This notice is not intended to prevent you from using the software and documents in this package, but to ensure that there are no misunderstandings about terms and conditions of such use.

* Please read the following notice carefully. If you do not understand any portion of this notice, please seek appropriate professional legal advice before making use of the software and documents included in this software package. In addition to whatever other steps you may be obliged to take to respect the intellectual property rights of the various parties involved, if you do make use of the software and documents in this package, please give credit where credit is due by citing this package, its authors and the URL or other source from which you obtained it, or equivalent primary references in the literature with the same authors.

* 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 correctness, merchantability or fitness for any particular or general use.

* 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.

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 the documentation; and

2. Give credit where credit is due citing the version and original authors properly; and

3. Do not give anyone the impression that the original authors are providing a warranty of any kind.

In addition, you may also modify this package and create derived works provided you do the following:

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

5. Make your modified source code available.

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 sold/distributed subject to the condition that it shall not, by way of trade or otherwise, be lent, re-sold, hired out or otherwise circulated without the supplier's prior consent, in any form of packaging or cover other than that in which it was produced. No part of this manual or accompanying software may be reproduced, stored in a retrieval system on optical or magnetic disk, tape or any other medium, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise for any purpose other than the purchaser's personal use.

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.

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 /iucr-top/cif/spec/index.html

[2] STAR File:

is a data file conformant to the file syntax defined at /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 /iucr-top/cif/spec/ddl/index.html

Last modified: 30 September 2000

IUCr Policy Copyright (C) 2000 International Union of Crystallography

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

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.

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 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 molecular coordinate files and interactively displays the molecule on the screen in a variety of representations and colour schemes. Supported input file formats include Protein Data Bank (PDB), Tripos Associates' Alchemy and Sybyl Mol2 formats, Molecular Design Limited's (MDL) Mol file format, Minnesota Supercomputer Center's (MSC) XYZ (XMol) format, CHARMm format, CIF format and mmCIF format files. If connectivity information is not contained in the file this is calculated automatically. The loaded molecule can be shown as wireframe bonds, cylinder 'Dreiding' stick bonds, alpha-carbon trace, space-filling (CPK) spheres, macromolecular ribbons (either smooth shaded solid ribbons or parallel strands), hydrogen bonding and dot surface representations. Atoms may also be labelled with arbitrary text strings. Alternate conformers and multiple NMR models may be specially coloured and identified in atom labels. Different parts of the molecule may be represented and coloured independently of the rest of the molecule or displayed in several representations simultaneously. The displayed molecule may be rotated, translated, zoomed and z-clipped (slabbed) interactively using either the mouse, the scroll bars, the command line or an attached dial box. RasMol can read a prepared list of commands from a 'script' file (or via inter-process communication) to allow a given image or viewpoint to be restored quickly. RasMol can also create a script file containing the commands required to regenerate the current image. Finally, the rendered image may be written out in a variety of formats including either raster or vector PostScript, GIF, PPM, BMP, PICT, Sun rasterfile or as a MolScript input script or Kinemage.

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.

• Running RasMol Under UNIX or VMS
• Running RasMol Under Microsoft Windows
• Running RasMol on the Apple Macintosh/PPC
• RasMol's Window
• Mouse Controls
• Scroll Bars
• Picking
• Dials Box
• Command Line Interface
• Dimensions within RasMol
• Start-up Initialisation Files
• Inter-Process Communication (IPC)

Running RasMol Under UNIX or VMS

     RasMol Molecular Renderer
     Roger Sayle, August 1995
     Copyright (C) Roger Sayle 1992-1999
     Version 2.7.2.1 April 2001
     Copyright (C) Herbert J. Bernstein 1998-2001
     *** See "help notice" for further notices ***
     [32-bit version]

If the program is run under the X Window System environment with a suitable colour screen, RasMol creates an additional window to display the rendered molecule interactively, as it is manipulated. If RasMol is not run under the X Window System, the program displays the message 'No suitable display detected!'. RasMol may be instructed not to display a graphics window by using the command line option '-nodisplay'. This is particularly useful for running RasMol as a background or batch process.

It is possible to specify either a coordinate filename or a script filename or both on the UNIX/VMS command line. A script file may be specified by adding the option '-script <filename>' to the command line. A molecule coordinate file may be specified by placing its name on the command line, optionally preceded by a file format option. If no format option is given, the specified coordinate file is assumed to be in PDB, CIF or mmCIF format. Valid format options include '-pdb', '-mdl', '-mol2', '-xyz', '- alchemy', '-charmm', '-mopac' and '-cif' which correspond to Protein Data Bank format, Molecular Design Limited's Mol file format, Tripos's Sybyl Mol2 file format, MSC's XMOL XYZ file format, Tripos's Alchemy file format, CHARMm file format, J. P. Stewart's MOPAC file format and IUCr CIF or mmCIF file format, respectively. If both a coordinate file and a script file are specified on the command line, the molecule is loaded first, then the script commands are applied to it. If either file is not found, the program displays the error message 'Error: File not found!' and the user is presented the RasMol prompt.

In order to leave RasMol, the user can type the command quit or exit at the RasMol prompt, and the program will return the user to the familiar unix prompt. Alternatively, if a prompt other than the main RasMol prompt is being displayed, the user may hit control-C (^C) to leave the program. The message '***Quit***' will be output to the terminal, before the usual unix prompt is redisplayed. The program may also be terminated by selecting the Quit menu option, on the bottom of the main menu.

Running RasMol Under Microsoft Windows

It is possible to specify either a coordinate filename or a script filename or both on the windows command line. A script file may be specified by adding the option '-script <filename>' to the command line. A molecule coordinate file may be specified by placing its name on the command line, optionally preceded by a file format option. If no format option is given, the specified coordinate file is assumed to be in PDB, CIF or mmCIF format. Valid format options include '-pdb', '-mdl', '-mol2', '-xyz', '- alchemy', '-charmm', '-mopac' and '-cif' which correspond to Protein Data Bank format, Molecular Design Limited's Mol file format, Tripos's Sybyl Mol2 file format, MSC's XMOL XYZ file format, Tripos's Alchemy file format, CHARMm file format, J. P. Stewart's MOPAC file format and IUCr CIF or mmCIF file format, respectively. If both a coordinate file and a script file are specified on the command line, the molecule is loaded first, then the script commands are applied to it. If either file is not found, the program displays the error message 'Error: File not found!' and the user is presented the RasMol prompt.

Running RasMol on the Apple Macintosh/PPC

Dragging and dropping multi-file 'movie' scripts onto aliases or copies of the RasMol application file may fail due to confusion about which is the correct script folder. Double-clicking on a script may lead to similar problems if copies are present.

Note that because on a Macintosh only one 'instance' of an application may be running at any one time, if you were double click on another file owned by 'RSML', the running copy of RasMol would zap its molecule and load the newly specified file.

RasMol's Window

While the mouse pointer is located within the graphics area of the main display window, the mouse pointer is drawn as a cross-hair cursor, to enable the 'picking' of objects being displayed; otherwise the mouse pointer is drawn as an arrowhead. Any characters that are typed at the keyboard while the display window is in 'focus' (meaning active or foreground) are redirected to the command line in the terminal window. Hence you do not need continually to switch focus between the command line and graphics windows.

The display window may be resized at any point during the session. This has the effect of simply rescaling the image displayed on the canvas. RasMol imposes limits on the size of the display window such that the window must be large enough to display the menu and scroll bars and yet small enough to fit on a single screen. Attempts to enlarge the screen may fail owing to insufficient memory on the host machine, in which case RasMol reports the error message 'Renderer Error: Unable to allocate frame buffer!' or some similar error.

On eight bit displays, when the number of colours required by the program exceeds the number of free colours on the screen, the program uses its own colourmap. This has the effect of temporarily displaying all windows other than the display window in false colours while the mouse pointer is within the display windows. If the mouse pointer is moved outside the display windows, the original colours of the other windows return, and the image on the canvas is shown in 'false colour'. Once the number of colours required by the program drops again, the presentation of colours returns to normal.

Mouse Controls

Scroll Bars

The normal behavior of the scroll bars can be changed by the 'rotate bond' and 'rotate all' commands and restored to normal operation by the 'rotate molecule' command. Alternatively the equivalent items in the "Settings" menu may be used. When 'rotate bond' is selected, the bottom scroll bar controls. rotation around a bond selected by the 'bond <src> <dst> pick' command (or by use of the "Pick Bond" item in the "Settings" menu). When 'rotate all' is selected, the scroll bars control rotation of all the loaded molecules instead of just rotating the currently selected molecule.

Picking

The program will display, in the terminal window, the atom's type, serial number, residue name and residue number. If the atom is a member of a named chain, the chain identifier is also displayed. Two examples of the output generated by selecting an atom are displayed below:

     Atom:  CA 349       Group:  SER 70
     Atom:  O  526       Hetero:  HOH 205    Chain:  P

Clicking the mouse on an atom can be used not only to identify it, but also to find the coordinates, the distances between two atoms (or to display a distance monitor), the bond angle defined by three atoms, the torsion angle defined by four atoms, to toggle labels on or off, to specify the centre of rotation, or to specify a bond as the axis of rotation. See the 'set picking' command for details.

Dials Box

The rotation about the X and Y axes automatically updates the indicators on the appropriate scroll bars. All the rotation dials rotate the molecule 180 degrees for a complete revolution of the dial. All the remaining dials clamp their values to permissible ranges; turning these dials past their limits has no effect. The centre of rotation of the molecule may be changed using the 'centre' command on the command line, or the command 'set picking centre' followed by a mouse click.

The 'ZOOM' dial allows the interactive zooming of the molecule between 10% and 200% of the original default magnification. Rotating the dial clockwise magnifies the molecule and anticlockwise shrinks it. A complete revolution of the dial corresponds to a 100% change in scale.

The 'SLAB' dial, which is only effective when slabbing is enabled, allows the user to move the front z-clipping plane from the nearest point on the molecule to the furthest. A complete rotation of the SLAB dial corresponds to moving the clipping plane half the distance between the front and back of the molecule. Turning the SLAB knob clockwise moves the clipping plane closer to the viewer (increasing the number of objects displayed), and turning it anticlockwise moves it further away (preventing more objects from being displayed). Slabbing mode is enabled by typing the command 'slab on' on the command line or toggling the slab option on the options menu.

Translation along the X and Y axis allows the centre of the molecule to be moved within the canvas area of the screen. Rotation and zooming are still performed relative to the centre of rotation and the molecule, respectively, which may often not be at the centre of the canvas. The TRANS Z dial currently has no effect.

Command Line Interface

If a syntax error is detected on entering an interactive command, RasMol indicates the location of the error on the command line by placing the '^' character under the offending word or character, and writing an error message on the following line. If a command is not recognised by RasMol, the program will generate an 'Unrecognised command!' error and redisplay the main prompt. If surplus information is given at the end of a command line, RasMol will execute the recognised command, but issue the warning message 'Warning: Ignoring rest of command!'. Some commands may prompt the user for more information. These commands display a different prompt and are discussed in the command reference.

Whenever RasMol outputs diagnostic or error messages to the screen owing to selecting options from the menu or picking objects on the screen, the current command line is cleared. The prompt is redisplayed after any text has been displayed.

Command Line Editing

RasMol maintains a history of recently used commands, so that the user never needs to type the same commands repeatedly. Typing ^P (Control-P) on the command line will display the previous command in the history and ^N will display the following command. These commands may be edited using the features described below. Moving forward or backward through the command history undoes the modifications made to the current line. The number of commands retained in the history depends upon their length. RasMol can retain more short command lines and fewer long ones.

Users with the Microsoft Windows version or the X windows version and with 'vt100' or compatible terminals (such as an 'xterm') can use the cursor control characters on the keyboard to abbreviate the control keys. The right and left cursor keys have the same affect as ^F and ^B, moving the cursor forward and back a single character, respectively. Similarly, the up and down cursor keys have the same function as ^P and ^N, producing the previous and next entries in the command history, respectively.

Users with the Macintosh version can use the four 'arrow keys' to move up and down through previous command line entries; and back and forth within a single command line statement. Hitting 'return' or 'enter' at any time will result in the execution of the current, e.g. selected or edited, command line contents.

Dimensions within RasMol

Start-up Initialisation Files

RasMol first looks for the initialisation file in the current directory and if it is not found will look for it in the user's home directory. On all systems the environment variable HOME may be used to name the user's home directory. If no personal initialisation file is found the program looks for the file rasmolrc (or RASMOLRC) in the RasMol system directory pointed to by the environment variable RASMOLPATH. This directory should also contain the on-line help file rasmol.hlp. On UNIX systems RASMOLPATH is typically set to be '/usr/local/lib/rasmol'.

Unlike the command 'script ".rasmolrc"', the program will not generate an error message if the file is not found. The system rasmolrc file is commonly used by system managers to display information about the local installation and who to contact for help. Such system rasmolrc files will contain RasMol 'echo' commands detailing a telephone number or e-mail address to be used for contacting somebody for local assistance.

Inter-Process Communication

When RasMol starts up on an X window system it registers itself with the X window Server as a Tcl interpreter. From within a Tcl application such as 'wish', you can use the Tcl command 'winfo interps' to determine the currently register interpreters on that display. The first instance of RasMol registers itself as 'rasmol', the second as 'rasmol #2', the third as 'rasmol #3' and so on. The Tcl interpreter can easily send a command to rasmol using the built-in 'send' command. RasMol interprets the string parameter to the send command not as a Tcl function to execute but as a RasMol command. Hence, typing 'send {rasmol} {background red}' into the wish interpreter will cause RasMol's display window to change colour. Using the same encoding as Microsoft's DDE Execute protocol, multiple commands may be sent in a single 'send' by placing the consecutive commands in square brackets. RasMol will execute all of the commands in a 'send' before refreshing the screen.

Under Microsoft Windows, RasMol supports a complete DDE protocol. The simplest layers of the protocol may be accessed by sending a DDE Execute command to application 'RasWin' and any topic. This will start a DDE conversation with the most recently launched instance of RasMol. Although any topic name can be used, the use of 'System' and/or 'RemoteControl' are recommended. Once again the contents of the execute package consists of a string for RasMol to execute. If the first non-whitespace character is an open bracket, the string is interpreted to be a sequence of consecutive commands enclosed in square brackets; otherwise the string consists of just a single command. Commands in square brackets may optionally be separated by whitespace and/or semi- colons. RasMol can also act as a 'data server' supporting hot, cold and warm links. Currently supported DDE items include 'Name', 'Image', 'Pick', 'Count' which denotes the Molecule name, the currently displayed image (in Microsoft DIB format), the atom expression of the last picked atom (or an empty string) and the number of selected atoms, respectively. Using a hot or warm link on the 'Pick' item, for example, allows an application such as Microsoft Word, Excel or Visual Basic to respond each time the user clicks on an atom in RasMol.

RasMol on the Apple Macintosh supports AppleEvents. Currently the only supported AppleEvents are the four 'core' events, Open Application, Open Document, Print Document and Quit. However, because OpenDocument determines its actions by the file's type signature this can be used to implement generic IPC. Because RasMol for the Macintosh treats all files of type 'RSML' as scripts, the sending application need only place all the commands to be executed in a temporary file, set the type of the file to 'RSML' and then send RasMol an OpenDocument AppleEvent with the file as parameter.

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

Syntax:  backbone {<boolean>}
         backbone <value>
         backbone dash

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 Ångstrom or RasMol units. A parameter value of 500 (2.0 Ångstroms) 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.

Syntax:  background <colour>

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.

Syntax:  bond <number>  <number> +
         bond <number>  <number> pick
         bond rotate {<boolean>}

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.

Syntax:  cartoon {<number>}

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.

Syntax:  centre {<expression>} {translate|center}
         center {<expression>} {translate|center}

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 Ångstrom) 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.

Syntax:  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 transfering 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.

Syntax:  colour {<object>} <colour>
         color {<object>} <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' 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>'.

Syntax:  connect {<boolean>}

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.

Syntax:  define <identifier> <expression>

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.

Syntax:  depth {<boolean>}
         depth <value>

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.

Syntax:  dots {<boolean>}
         dots <value>

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.

Syntax:  echo {<string>}

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.

Syntax:  English

The RasMol 'English' command sets the menus and messages to the English versions. The commands 'French', 'Italian' and 'Spanish' may be used to select French, Italian and Spanish menus and messages.

Syntax:  French

The RasMol 'French' command sets the menus and messages to the French versions. The commands 'English', 'Italian' and 'Spanish' may be used to select English, Italian and Spanish menus and messages.

Syntax:  hbonds {<boolean>}
         hbonds <value>

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.

Syntax:  help {<topic> {<subtopic>}}
         ? {<topic> {<subtopic>}}

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

Syntax:  Italian

The RasMol 'Italian' command sets the menus and messages to the Italian versions. The commands 'English', 'French' and 'Spanish' may be used to select English, French and Spanish menus and messages.

Syntax:  label {<string>}
         label <boolean>

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 (similar to C's printf syntax). 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. RasMol uses the label '%n%r:%c.%a' if the molecule contains more than one chain, '%e%i' if the molecule has only a single residue (a small molecule) and '%n%r.%a' otherwise.

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.

The following table lists the current expansion specifiers:

    %a      Atom Name
    %b %t   B-factor/Temperature
    %c %s   Chain Identifier
    %e      Element Atomic Symbol
    %i      Atom Serial Number
    %n      Residue Name
    %r      Residue Number
    %M      NMR Model Number (with leading "/")
    %A      Alternate Conformation Identifier (with leading ";")

Syntax:  load {<format>} <filename>

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 5 molecules may be loaded at a time. To delete a molecule prior to loading another use the RasMol 'zap</