- Chimera-users - RBVI Mailing Lists

1.2251 snapshot release
by Eric Pettersen 06 Jun '06

06 Jun '06

Hi all, There is a new snapshot release (1.2251) available, with a potpourri of new features, listed below. The release is for all platforms, but on Mac we had a little difficulty getting things to work for OS X 10.3, so this release is 10.4 only, but the next production release will include 10.3 support. --Eric Eric Pettersen UCSF Computer Graphics Lab pett(a)cgl.ucsf.edu http://www.cgl.ucsf.edu --- 1.2251 release (changes since 1.2199 release) GENERAL: Session files are smaller, use less memory, and start faster. CIF/mmCIF files can be read (or fetched by ID from RCSB) Electron density maps can be fetched by PDB ID from Electron Density Server Virus Particle Explorer (VIPER) files can be fetched by ID VIPER input automatically starts Multiscale Models and constructs viral capsid Thinner default ribbons Files opened by scripts (either Python or Chimera commands) are now searched for relative to the script location, not Chimera's startup location. Can switch to sequential stereo mid-session without having used --stereo at startup (except on certain Windows systems) New stereo mode: anaglyph (offset red/cyan-tinged views, like 3D movies) NEW TOOLS: Add Charge (Structure Editing) - assigns partial charges to atoms; Amber (Cornell et al. 1995) charges used for standard residues, Amber's Antechamber module (now included with Chimera) used to calculate charges for nonstandard residues Build Structure (Structure Editing) - under construction but basic functions work; not much documentation ReadStdin (Utilities) - allows communication with Chimera through standard input/output TOOL CHANGES: AddH (Structure Editing) - new options including how to treat histidines Adjust Torsions (Structure Editing) - interface reorganized to show atoms defining a torsion in order 1-2-3-4 - options added to control decimal places and show degree symbol in angle labels Dock Prep (moved to Structure Editing) - option added to delete alternate locations of atoms - hydrogen addition and charge addition details split off into separate tools called from Dock Prep (AddH and Add Charge, respectively) - terminal carboxylates/amines completed as appropriate Effects (Viewing Controls) - background transparency option added (previously only available as --bgopacity startup option) Minrms Plot (Structure Comparison) - Show Alignment option added MPOSE extension removed (Structure Comparison) Multalign Viewer (Structure Comparison) - .ali extension interpreted as PIR format - .pfam extension no longer indicates Stockholm format, instead indicates Pfam format ("Plain Pfam format" at the Sanger Institute Pfam site) - changed default residue letter/region colors for improved readability - improved editing response time - editing no longer pushes residues that are not in the active region - added control over whether a region depiction spans gaps - option to associate a structure chain with the best-matching sequence in the alignment (when criteria for automatic association are not met) - new Edit menu allowing sequence reordering and deletion, gap column addition and deletion COMMAND CHANGES: ribbonjr removed NEW COMMANDS: addcharge - assign partial charges to atoms (command-line implementation of new Add Charge tool) intersurf - generate and display interface surfaces (command-line implementation of Intersurf) setattr - set a new or existing attribute to a specified value surftransparency - adjust molecular surface transparency COMMAND CHANGES: longbond - now takes an atom or model specification to restrict the calculation to certain models TUTORIALS: figures added to Getting Started tutorials

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Stereographics support
by Eduardo Sanz Garcia 01 Jun '06

01 Jun '06

Hi, We've recently purchased a Stereographics E-2 Emitter to go with our Mac G5 equipped with an NVIDIA Quaddro FX 4500 Graphics Card. As far as we know, the hardware is hooked up correctly, but when we try to run Chimera using command "./chimera --stereo", the following error appears: 'Unable to find hardware stereo support TOGL Couldn't get visual' We called the Stereographics company regarding this error and they mentioned that our software should have "blue line code" enabled. They couldn't give me more details because they said they were unfamiliar with Chimera. Could someone enlighten us with how we can get Chimera to run with stereo enabled? Thanks.

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-S option in ksdssp command
by kovzany＠go.com 01 Jun '06

01 Jun '06

Dear All, I'm trying to get an output with protein secondary structure assignment into a text file, using ksdssp command, unfortunately everytime I get error like this: Computing secondary structure assignments for model #0 using ksdssp (Kabsch and Sander Define Secondary Structure of Proteins) with the parameters: energy cutoff <default> minimum helix length <default> minimum strand length <default> -S option not yet available My question is: am I doing something wrong, or -S option is not yet implemented, despite it is described in ksdssp.html help file? thanks, PK

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Question regarding an inorganic compound to display with Chimera
by Allen Stock 26 May '06

26 May '06

HI, I'm interested in viewing the 3D structure for the following inorganic component: Tantalum Pentaethoxide ... also known as TAETO The following company gives a 3D representation of the compound. Any idea where I can find a 3D description that can be displayed with Chimera. Thanks for your attention and feedback. Regards, --Allen

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editing Python saved sessions
by Jonathan Hilmer 22 May '06

22 May '06

Notepad++ will do a great job of editing the .py files. I've found that this is an extremely convenient way to accomplish certain tasks, such as precise alignment of multiple clipping planes. However, you definitely have to know what you're looking for when digging through the files. On a related issue, I have a question regarding the saved sessions. In some of the viral capsid models I've created a saved session is enormous (about 60 megabytes) and fails to compile either automatically when loading the .py session or manually using the python.exe included with Chimera. It seems to be a result of excessive explicit attribute assignments that I don't really care about (color etc) since they are easy enough to set once the model has loaded. Does anyone have any suggestions or experience with this issue? Jonathan PS: Check out the most recent issue of Science. Although the editors chose the least visually impressive submission, non of the variations would have been possible without Chimera: great program. > Hello. My name is Anne Szklarski and I am a student at The College of New > Jersey. I was wondering if there was a way that the python files could be > modified in notepad. Does it require the Python software? The reason I ask > is because I have been renaming certain atoms in the .ent files using > notepad so that I may specifically select them in chimera. The only > problem with my current method is that I have to start the rendering > process from the beginning which is quite time consuming. So I was > wondering if there was a way that I could alter the chimera file directly > and not lose any of the colors, etc. that I have chosen. I appreciate any > information on this matter. > > Thank you, > Anne Szklarski

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Question
by szklars2＠tcnj.edu 21 May '06

21 May '06

Hello. My name is Anne Szklarski and I am a student at The College of New Jersey. I was wondering if there was a way that the python files could be modified in notepad. Does it require the Python software? The reason I ask is because I have been renaming certain atoms in the .ent files using notepad so that I may specifically select them in chimera. The only problem with my current method is that I have to start the rendering process from the beginning which is quite time consuming. So I was wondering if there was a way that I could alter the chimera file directly and not lose any of the colors, etc. that I have chosen. I appreciate any information on this matter. Thank you, Anne Szklarski

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Problems installing/running chimera
by Christian Schafmeister 21 May '06

21 May '06

Hi there, I tried installing the latest snapshot of chimera for windows: chimera-1.2224-win32.exe as well as the production release 1.2199 and I get an error when it tries to start up. Dialog box: pythonw.exe - Entry Point Not Found The procedure entry point ?pathSeparator@PathFactory@otf@@SADXZ could not be located in the dynamic link library libotf.dcl When I try chimera --debug I get File "C:\Program Files\Chimera\share\chimera\__init__.py", line 15 in ? from _chimera import * ImportError: DLL load failed: The specified procedure could not be found. Return code: 1 I have python 2.4.2 already installed on my machine, is that causing a problem? Cheers, .Chris. -- Christian E. Schafmeister, Ph.D. Assistant Professor Chemistry Department University of Pittsburgh

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Chimera crash on SGI
by Thomas Goddard 19 May '06

19 May '06

Hi Jean-Fracois, If Chimera is crashing your SGI when using solid volume display this is almost surely a problem with your graphics driver. Are you using the IRIX operating system? Which version? Our documentation claims that IRIX 6.5.10 is needed but it may be that a more recent version is actually necessary to avoid the system crash you observe. If you are using an SGI Octane or similar vintage machine I would recommend you find a Windows, Mac, or Linux alternative since the graphics speed will be much better with a consumer graphics card. Tom > Date: Thu, 18 May 2006 14:25:57 -0400 (EDT) > From: jean-francois menetret <menetret(a)bu.edu> > To: Thomas Goddard <goddard(a)cgl.ucsf.edu> > Subject: Re: Volumes shown in Model Panel > > Hi Tom, > > I tried the version 1.2224 on a PC, it works very nicely > Would it be much trouble to have the snapshot compiled for SGI ? > It has been more convenient for me to work on an SGI except for a small > problem: if I click on solid (in the volume viewer), the whole machine=20 > crashes :-( > > best wishes > > Jean-Fran=E7ois

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Volumes shown in Model Panel
by Thomas Goddard 17 May '06

17 May '06

Hi Jean-Francois, I made a change after Chimera version 1.2199 that keeps the volume data sets in the Model Panel even when you press the Unshow button in the volume dialog. So the Model Panel and volume dialog menu should always list the same data sets. You need Chimera snapshot version 1.2224 which is on the download page below the production releases 1.2199 to get this improvement. In 1.2199 pressing the volume dialog unshow removes the volume from the Model Panel list. Tom > Date: Wed, 17 May 2006 11:03:30 -0400 (EDT) > From: jean-francois menetret <menetret(a)bu.edu> > To: Thomas Goddard <goddard(a)cgl.ucsf.edu> > Subject: question > > Hi Thomas, > > is there a way to keep the model panel list and the data sets list=20 > (from volume viewer) in sync ? > > Best wishes > > Jean-Franncois

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Chimera movie commands
by Thomas Goddard 16 May '06

16 May '06

Hi Frank, There are currently no Chimera commands for volume surfaces, and there are not commands to control per-model clipping. We wish to add these commands and others so that movie making is more powerful. Currently we are writing a renewal of our major 5-year grant due June 1 so it will probably not be possible for me to add these commands before then. Here is what is available now. There is a command for changing isosurface threshold level. It is part of "Animation commands" on the Chimera experimental features page. http://www.cgl.ucsf.edu/chimera/experimental/experimental.html It is not part of any Chimera distribution but can be downloaded separately and use with your current Chimera. The most practical way to gradually change from a surface to mesh would be to open the model twice, then gradually change the mesh color from completely transparent to opaque, then gradually change the surface from completely opaque to completely transparent. You can't do those two steps simultaneously because Chimera unfortunately does not correctly display two transparent models -- only one at a time. There are no commands to do volume surface color fades. You can do the color fades though using the Chimera animation editor called EMANimator distributed with EMAN. http://ncmi.bcm.tmc.edu/~stevel/EMAN/doc/ Get the latest EMAN distribution (nightly build) because it also is able to move per-model clip planes. To use EMANimator you install EMANimator the use Chimera menu Favorites / Preferences, category tools and add the EMAN chimeraext directory /usr/local/EMAN/chimeraext to the list of locations Chimera looks for extensions in. Here is some documentation I wrote for an older EMANimator version. http://www.cgl.ucsf.edu/chimera/related/emanimator/emanimator.html This is not an entirely trivial tool to use. It lets you create a timeline of transitions and preview them, and record a movie. The drawback is that it only supports a limited set of smooth transitions, mostly related to volume data display. It does not for instance handle 2D labels. Maybe you could add those in an external movie editor. Using EMANimator is a totally separate option from using Movie Recorder and commands. If you want to know all the current Chimera commands with "frame" options that can do transitions it is a short list: http://www.cgl.ucsf.edu/chimera/docs/ContributedSoftware/recorder/moviecomm… Unfortunately our animation tools are quite primitive now and you will need to make compromises if you want to use them. We are proposing to significantly improve animation capabilities in our new grant and will work on it even before then. So feedback about what is important to you is welcome. Tom ------------- > To: Thomas Goddard <goddard(a)cgl.ucsf.edu> > From: Frank Alber <frank(a)salilab.org> > Subject: chimera movie question > Date: Tue, 16 May 2006 17:39:15 -0700 > > Hi Tom, > I have a question about chimera. I need to make some movies with > chimera in which I like to switch on and off different models (using > the volume viewers volume densities) maybe introduce per-model clipping > and add and remove 2d labels during the movie. I figured out how to > rotate scale and move the model around based on command lines commands > that I read in as a file. Also, how to switch the model in the model > panel on and off. > But is it possible to use volume viewer commands on the command line? > So I could use them in a command file? For example switch the > representation of model 1 from surface to mesh. If so, is it possible > to change representations over a number of frames, so that they blur > into each other? Like the 'visibility show frames 100' option in the > 2dlabels command? I couldn't find such options in the manuel but I am > not sure if I looked careful enough. > In case, do you know anybody who I could ask for some cmd files (used > for moviemaking) that actually do similar stuff and which I could look > at as template examples? That would be great starting point to see what > commands could be useful for making movies. > I found an example on the web page, but it didn't have volume viewing > options there. > Thanks a lot! > Frank > > --- > Frank Alber > Andrej Sali Lab > California Institute for Quantitative Biomedical Research > University of California at San Francisco > QB3, Box2552 > 1700 4th Street, Room 501 > San Francisco, CA 94143-2552 (CA 94158 for courier delivery), USA > Phone: +1 (415) 514 4258 > Fax: +1 (415) 514 4231

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proposed "backbone" change
by Eric Pettersen 15 May '06

15 May '06

Hi all, RIght now, if you do "Actions->Atom/Bonds->backbone only" Chimera shows the minimum number of atoms to produce a connected peptide/ nucleic acid backbone, which therefore does not include peptide carbonyl oxygens nor nucleic sugar rings/charged phosphate oxygens. We are thinking of changing the behavior so that "backbone only" includes everything that isn't in the side chain/base. The question is: does anyone need/want the current behavior? If not, I'd not only change "backbone only" but would also change Select->Structure- >backbone from a menu (has "full" and "minimal" in it) to just a menu item that selects the full backbone. If there are some people who do use the current behavior, then instead I'd change "backbone only" to be a menu too. --Eric Eric Pettersen UCSF Computer Graphics Lab pett(a)cgl.ucsf.edu http://www.cgl.ucsf.edu

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Non-gui chimera in a shell?
by James Vincent 09 May '06

09 May '06

Hello, I've read several threads about nongui use of chimera and that some work was started. This work seemed mainly aimed at getting a web server script to run chimera and return some result back to a browser. I'm interested in running chimera in a stand alone python script. I'd like to do molecular calculations using the various tools but all on a command line, no graphics. It seems the --nogui option would get this, but the OS X version does not seem to implement that. Perhaps I'm missing something. Can anyone help? ideally I'd like to just have a plain python script that imports the chimera package but does not choke on all the graphics stuff, and then lets me use the chimera object model and other programming objects. Thanks for any assistance, Jim ---- James J. Vincent, Ph.D. National Cancer Institute National Institutes of Health Molecular Modeling and Bioinformatics Section Laboratory of Molecular Biology Building 37, Room 5120 37 Convent Drive, MSC 4264 Bethesda, MD 20892 USA 301-451-8755 jjv5(a)nih.gov

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manual
by Oscar Moran 08 May '06

08 May '06

does exists a printable version of the manual? (pdf, ps or even simple ascii) oscar Oscar Moran, PhSc Istituto di Biofisica Consiglio Nazionale delle Ricerche Via DeMarini, 6 I-16149 Genova, Italy Tel. +39-0106475-558 / 522 Fax +39-0106475-500

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transparency at the command line
by Miguel Ortiz-Lombardia 07 May '06

07 May '06

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi chimerics, I'm not very familiar (yet) to python scripting in chimera, so I am trying to prepare a movie using just line commands in a file. I would like to gradually increase the transparency of a model's surface that has been colored in "rainbow by residue" style. My question is then: is there a way to control the overall transparency of a surface from the command line? I could resort to colordef commands at every step, but this would make things very hard with the rainbow coloring... Thanks a lot! Miguel ( trying to learn more python in the meantime ;) ) - -- Miguel Ortiz Lombardía Centro de Investigaciones Oncológicas C/ Melchor Fernández Almagro, 3 28029 Madrid, Spain Tel. +34 912 246 900 Fax. +34 912 246 976 e-mail: molatwork(a)yahoo.es - ---------------------------------------------------------------------- Et ainsi ne pouvant faire que ce qui est juste fût fort, on a fait que ce qui est fort fût juste. Blaise Pascal, Pensées -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (Darwin) iD8DBQFEXaezF6oOrDvhbQIRAnUNAJ9UJOF3RWv7ohXj+pcmQeD6rU4VBwCfb7PK PDzmG1mMWWL6iW9o+a+ooXk= =Flu6 -----END PGP SIGNATURE-----

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B-factors
by Narender Singh Maan 05 May '06

05 May '06

Dear Chimera users, i am looking for a way to write down the average B-factors for each residue from a pdb file (which shows atomic bfactors). I tried using chimera attributes which can color the protein and shows a histogram for bfactors, but i am not able to get those average values in reply log or some other written file. Please let me know if i can get any help in this. thanxs ns

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Chimera under KDE (update)
by Mingfeng Yang 05 May '06

05 May '06

Please disregard my previous message. I just tried to kill the KDE system process one by one and found out that skim (an input program) is the one should be blamed. Mingfeng

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Can't input anything under KDE
by Mingfeng Yang 05 May '06

05 May '06

I am using Chimera build 2199 under KDE 3.5.2, and I can't input anything into the command line (and other input dialogs) of chimera. The linux distribution is Kubuntu Dapper Drake. If I get into the KDE environment with failsafe mode, everything is fine. And I remember chimera works fine under KDE 3.5.2 under gentoo. I guess some service(s) of KDE must have confliction with chimera, but I couldn't figure out which one. :( Best, Mingfeng

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absolute scale?
by Cathy Lawson 02 May '06

02 May '06

Hi, Is there a way to set an "absolute scale" for viewing in chimera? I'm trying to make pictures in multiple Chimera sessions with different molecules and would like for the results to be all on the same scale. I naively thought I could do this with the "camera" scale but then I noticed that for two different sessions where this value was set to 1.0, the actual scales are quite different. Chimera help revealed that the camera scale is relative to the original size when the model was first opened. Any suggestions would be appreciated! thanks, Cathy Lawson *********************************************************************** Catherine L. Lawson Laboratory for Structural Biology and Bioinformatics Department of Chemistry and Chemical Biology Rutgers University 610 Taylor Road, Piscataway, NJ 08854 cathy.lawson(a)rutgers.edu tel 732 445 8074 fax 732 445 5312 http://rutchem.rutgers.edu/~lawson http://roma.rutgers.edu/~lsbb *********************************************************************

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Broken labels!
by Changhoon Kim 02 May '06

02 May '06

Hello? I am using Chimera on Windows XP. It's "beta version 1 build 2199 2006/01/24". When I tried to display residue labels, many of the labels were unrecognizable. I've attached the picture showing the broken labels. Sometimes the distance labels are also unrecognizable. I hope it would be fixed soon. Regards Changhoon Kim

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libGL.so
by Isaac Amela Abellan 02 May '06

02 May '06

Hello, I'm using Linux and when I had tried to execute chimera this message appeared: "OpenGL misconfiguration detected. /usr/lib/libGL.so.1 differs from /usr/X11R6/lib/libGL.so.1. Please read installation instructions." I said it several times to my system administrator and he solved it using your instructions (see below): "If Chimera terminates with the error OpenGL misconfiguration detected, that means that you have two different versions of libGL.so installed -- one in /usr/lib (installed by your graphics card drivers) and one in /usr/X11R6/lib (possibly installed by Mesa, which if so would mean no hardware graphics acceleration if this version were used). Reinstalling your graphics card drivers should remove the /usr/X11R6/lib version. Alternatively, you could rename or remove the /usr/X11R6/lib version yourself. With the latter approach you might want to verify that all OpenGL applications that you use continue to work before permanently removing the library. On startup, you may see the warning Xlib: extension "Xfre86-DRI" missing on display "0.0". That means that there was no graphics driver found for your card that uses the DRI, direct rendering interface, technology for fast 3D graphics. The solution is to either ignore the warning or to upgrade your hardware and software (see Mesa/OpenGL issues below)." The problem is that when I reboot my computer the problem still appears and we should do the same procedure explained above. We can't configure the system conservating the libraries of my card drivers (/usr/lib) without removing the Mesa ones (/usr/X11R6/lib). How can we solve the problem? We will be waiting for your response. -- ------------------------------------------------ Isaac Amela Abellan PhD Student Laboratory of Bioinformatics Institute of Biotechnology and Biomedicine (IBB) Autonomous University of Barcelona (UAB) 08193 Bellaterra, Barcelona. Spain. Phone: 34-93-5812807 e-mail: iamela(a)bioinf.uab.es ------------------------------------------------

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Stereo angle value
by Prof. Fabrizio Briganti 02 May '06

02 May '06

Hi, I have not been able to find any reference to the value for the angle difference between Right and Left views in Stereo Images made with Chimera. Can you help me find it? Is there any way to change such angle value? Thanks Fabrizio

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Paper virus models
by Thomas Goddard 02 May '06

02 May '06

I made a Chimera tool that flattens icosahedral virus models. Printing, cutting, folding, and taping produces a paper model. http://www.cgl.ucsf.edu/chimera/experimental/flatten_icosahedron/flaticos.h… The flatten icosahedron tool can be downloaded from the Chimera experimental features web page: http://www.cgl.ucsf.edu/chimera/experimental/experimental.html Tom

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writing mrc files
by Eran Shacham 21 Apr '06

21 Apr '06

Hey there, I am trying to write an mrc file using the write_mrc2000_grid_data module. My function is below. My array of data is a <scitbx_array_family_flex_ext.double object at 0x58b9502c>. Which is a basically a matrix with dimensions: (243, 243, 243). When trying to write an mrc file using this array I get the following error: ************************* File "/home/eshacham/cctbx/mrc_functions.py", line 20, in write_mrc write_mrc2000_grid_data(g, path) File "CHIMERA/share/VolumeData/mrc/writemrc.py", line 44, in write_mrc2000_grid_data File "CHIMERA/share/VolumeData/arraygrid.py", line 48, in submatrix ValueError: need more than 1 value to unpack Code used *********************** def write_mrc(data): print data origin = (1.54, 2.45, 3.45) # XYZ coordinates of array index (0,0,0) step = (.25, .25, .25) # Spacing between grid points import Numeric a = Numeric.array(data, Numeric.Float32) arrays = [a] import VolumeData g = VolumeData.Array_Grid_Data(arrays, origin, step) path = '/home/eshacham/structures/result.mrc' from VolumeData.mrc import write_mrc2000_grid_data write_mrc2000_grid_data(g, path) I am assuming that it has to do with my array dimensions. Any help would be greatly appreciated. Cheers, Eran.

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Re: [Chimera-users] Rotation about an axis
by Thomas Goddard 21 Apr '06

21 Apr '06

Hi Jordan, Aha! It turns out I wrote code that does exactly what you want last year. It is called the symmetric molecule copies command at the bottom of the Chimera experimental features web page: http://www.cgl.ucsf.edu/chimera/experimental/experimental.html It is not distributed with Chimera yet but you can download it on that page and install it with your existing Chimera. I hate to discourage you from Python programming in Chimera but I think this is just what you need. You open one copy of your molecule and then use this "sym" command to make the hexamer. Then when you move the original copy of the molecule relative to your map, the other 5 copies automatically reposition to maintain the 6-fold symmetry. To get a more detailed description look at the "details" link on the experimental features page. The hexamer symmetry comes from the BIOMT matrices in the PDB file. This sym command treats those matrices in the coordinate system of the density map (yes, a bit weird). The key here is to make sure the symmetry axis of the density map matches the symmetry axis of the BIOMT matrices. The easiest approach is probably to make the BIOMT matrices produce a hexamer about the z-axis through (0,0,0). When you open your density map in Chimera it may not have the hexamer density centered at (0,0,0). You will need to adjust its origin so the density hexamer is centered at (0,0,0). Use the volume dialog menu entry Features / Origin and Scale to adjust the position of the lower left front corner of the map. Assuming the hexamer is centered in a 128 x 128 x 100 grid with voxel size 0.8 angstroms you would set the origin to (-50.8, -50.8, -39.6) = (-63.5 * 0.8, -63.5 * 0.8, -49.5 * 0.8). The weird 63.5 = 128/2 - .5 instead of 64 = 128/2 is easiest to understand if you think of a map that is only 2 by 2 by 2 in size. Remember to press the Enter key in one of the origin fields in the volume dialog to have the new position take effect. In any case that may still be a half voxel off depending on your map, or it may be way off. Of course you have to know the position of the center of the hexamer in your density to make this work. A way to verify that you have set the correct origin is to open 2 copies of the map -- set the map origins, then use constrained move to rotate just one copy keeping the other one fixed. It is easy then to visually see if the two copies are concentric. For convenience you can save your map as an MRC file with the new origin with the volume dialog File / Save As... menu entry. Saving a Chimera session also saves the origin in the Chimera session file (the map is not modified). I can see various troubles with using the Multiscale tool. First Multiscale low resolution surfaces are not reliably synchronized to the individual PDB models. If you change a PDB model position Multiscale won't realize it and the low resolution surface will not move to the new location. If you are using the latest Chimera snapshot (1.2224, April 10, 2006) then the problems will be even more severe because I changed the way Multiscale positions PDB models. Instead of setting the pdb_model.openState.xform it changes the atom coordinates of the model (setting atom.coord = x,y,z). All the xforms of the 6 models in a hexamer would be the same in Chimera 1.2224. This change was made to allow correctly moving individual chains of multiscale models, possible with the "movement mouse mode" feature on the experimental features web page. Lastly some clarification about Chimera's coordinate systems. First there is a global Chimera coordinates system with the x axis always horizontal relative to your graphics window, the y axis always vertical, and the z axis always pointing out of the screen at you. When you rotate models with the mouse, this coordinate system does not change -- the individual matrices positioning the models are changed. The origin of this global coordinate system is not necessarily in the center of the screen. It can be anywhere including off-screen. The global coordinates for the center of the screen are set to match the center of the bounding box of the first model you open in Chimera. Besides the global coordinate system each model has a local coordinate system. With a PDB file, the atom coordinate positions are in the local coordinate system. If you open a PDB model in Chimera and rotate it, the atom.coord x,y,z values do not change -- they are expressed in the local coordinate system which is fixed to the atoms and rotates with the model. (You can however change the atom.coord positions using Python code.) The pdb_model.openState.xform 3 row by 4 column matrix gives the rotation and translation that maps the local coordinates (e.g. a PDB atom position) into Chimera global coordinates. Other types of Chimera models like density maps are just like PDB models having a local coordinate system -- the density map grid points have unchanging coordinates in the local coordinate system. More than you wanted to know. Tom > Date: Thu, 20 Apr 2006 19:51:40 -0700 > From: "Jordan Benjamin" <jordan.benjamin(a)gmail.com> > To: "Thomas Goddard" <goddard(a)cgl.ucsf.edu> > Subject: Re: [Chimera-users] Rotation about an axis > > Ah, it looks like it still works for normal models. The weird behavior > was with a model that had been generated with the Multiscale Models > tool from crystal contacts. I still wish I understood the > global-vs-local issue better though. > > > On 4/20/06, Jordan Benjamin <jordan.benjamin(a)gmail.com> wrote: > > Thank you for your help on this. I have a further question. Basically, > I'm trying to dock into electron density the crystal structure of a > protein that forms a hexamer. I would like to be able to have six > copies of the monomer structure loaded at once, and when I move or > rotate one copy, I'd like to be able to transform the other five to > match. So, I thought the ConstrainedMove code would be a good starting > point, since what I'm trying to do is the same thing it does, just > with the rotation specified by degrees instead of by dragging the > mouse. > > After you sent the email below, I modifed the function I was writing > accordingly, and it worked. However, I'm trying to use it now, and > it's not working. I'm a little lost on debugging it, because I don't > even know what Chimera's concept of a global coordinate system is, nor > do I have any way to visually display the local origin and axis for > each object. Is there a way to do these things that you know of? Do > you know of a simple way to rotate an object X degrees around a > specified axis (relative to another object if needed)? > > If these are really hard questions and the answer is just that I > should read the source code until I figure it out, that's totally > fine. I just thought I'd ask. > > At least with Chimera the code IS available, unlike the situation with > Amira where things would be undocumented and broken, and there'd be no > way to fix them... > > Thanks so much, > Jordan > > The function I was using is as follows (yes, it's brittle and ugly, > but it's all I had time for): > def update_hexamer(ref_model,model,*rest): > origin = (0,0,0) > axis = (0,0,1) > angle_deg = 60 > > mvo = chimera.Point(*origin) > vo = ref_model.openState.xform.apply(mvo) > mva = apply(chimera.Vector, axis) > va = ref_model.openState.xform.apply(mva) > > xf_original = model.openState.xform > > for i in range(5): > xf = chimera.Xform() > xf.translate(*vo) > xf.rotate(va, angle_deg+60*i) > xf.translate(-vo.x, -vo.y, -vo.z) > model.openState.globalXform(xf) > rest[i].openState.xform = model.openState.xform > model.openState.xform = xf_original >

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Re: [Chimera-users] Sum of volume data values
by Thomas Goddard 13 Apr '06

13 Apr '06

Hi Eran, Ok, here is code to read an MRC file and print the sum of map values without using Chimera. You need Python, the Numeric Python module which handles multidimensional arrays and the VolumeData module from Chimera. Numeric is obtained from sourceforge: http://sourceforge.net/project/showfiles.php?group_id=1369&package_id=1351 The VolumeData module is in your Chimera distribution. chimera/share/VolumeData Here's an example running the script where I've set PYTHONPATH to have access to the VolumeData module: % env PYTHONPATH=/usr/local/chimera/share python2.4 volumesum2.py Sum of values of groel.mrc = 21720.8984375 Send future questions to chimera-users(a)cgl.ucsf.edu so others who have similar problems can benefit. I get that email just as fast. Tom ------- file volumesum2.py follows: # Script to print the sum of volume data values. # Does not need Chimera, just the VolumeData module and Numeric and Python. path = 'groel.mrc' # Read the MRC volume data and get the 3-D Numeric array. from VolumeData.mrc.mrc_format import MRC_Data data = MRC_Data(path) m = data.matrix() # Compute the sum of the elements of the volume matrix. import Numeric sum = Numeric.sum(m.flat) # Print the sum print 'Sum of values of', path, ' = ', sum ------- > Date: Wed, 12 Apr 2006 14:46:14 -0700 > From: Eran Shacham <eshacham(a)burnham.org> > To: Thomas Goddard <goddard(a)cgl.ucsf.edu> > Subject: Re: Sum of volume data values > > Hey Tom, > > Thanks for your reply. However, I would like to do that from within a > script I already wrote. i.e I would like to integrate a read_in method > for an MRC file, access it values and then calculate the sum. I would > like to avoid doing that by opening my file in Chimera at this stage of > the program. Can it be done by importing some of your code? > > Thanks, > Eran.

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