April 2005 - Chimera-users - RBVI Mailing Lists

Chimera Surface Area/Volume
by Elaine Meng 27 Apr '05

27 Apr '05

Hi Dieter, Just a few add-ons to Tom's reply: Another approach to getting the surface area of the receptor buried by the ligand is to run Surface Area/Volume (a) on the complex of ligand and receptor (must delete water and anything else first). Then use Attribute Calculator to sum the surface areas of the receptor atoms only. (b) after deleting ligand, run it again on the receptor. The total is all from the receptor, so it is not necessary to use Attribute Calculator. Subtract the value from (a) from this value. Tom gave a link to the development documentation, which is slightly ahead of the Chimera version you have. It is almost the same, except that the Tools menu has been reorganized. Probably in the version you have, both Attribute Calculator and Surface Area/Volume are in the Utilities submenu of the Tools menu. To get the documentation that goes with your version, use the Help buttons on those dialogs or open the User's Guide from the Help menu. If you have the latest snapshot (1.2105, March) there is an "Attributes" tutorial (Help... Tutorials). Part 2 has one example of using Surface Area/Volume and Attribute Calculator. Finally, if anything is confusing or hard to find in the documentation, please feel free to complain to me! 8-) Elaine ----- Elaine C. Meng, Ph.D. meng(a)cgl.ucsf.edu UCSF Computer Graphics Lab and Babbitt Lab Department of Pharmaceutical Chemistry University of California, San Francisco http://www.cgl.ucsf.edu/home/meng/index.html

1 0

buried surface area
by Thomas Goddard 27 Apr '05

27 Apr '05

Hi Dieter, The surface area / volume tool (menu entry Tools -> Utilities -> Surface Area / Volume) could give buried surface areas if you ran it for the unbound receptor, unbound ligand, and then the complex, and then calculated { Area(receptor) + Area(ligand) - Area(receptor+ligand) } / 2 When you use this tool it reports the total area to the Reply Log (menu entry Favorites / Reply Log) and atoms are assigned an attribute saying how much area they contribute. It is a bit of a pain to run it 3 times and do the math yourself. The surface area is calculated by a web server as described in the Chimera User's Guide http://www.cgl.ucsf.edu/chimera/docs/ContributedSoftware/surfvol/surfvol.ht… so you will need an internet connection to use it. The Chimera User's Guide is only available in HTML as far as I know. It is written in HTML. Tom > From: "Dieter Blaas" <dieter.blaas(a)meduniwien.ac.at> > To: Thomas Goddard <goddard(a)cgl.ucsf.edu> > Date: Wed, 27 Apr 2005 21:38:46 +0200 > Subject: buried surface area > > Hi Tom, > two quick questions: 1/ can Chimera calculate/display > the surface area buried by e.g. a ligand when bound on > a receptor? 2/ is there a documentation other than htlm > (e.g. pdf file)? > Thanx, Dieter >

1 0

Resize a molecule
by Thomas Goddard 27 Apr '05

27 Apr '05

Here is some code to scale a molecule size by a given factor. That is all atoms have their coordinates multiplied by a factor. Tom ------- Start of forwarded message ------- Date: Wed, 27 Apr 2005 11:05:55 -0700 (PDT) From: Thomas Goddard <goddard(a)cgl.ucsf.edu> Hi Jinghua, By "virus cage pdb file" I guess you mean you placed atoms at icosahedral positions, and want to show them connected up to show some icosahedral pattern. I think the easiest approach is to open your old session, run a command to change the diameter of the cage, then save a new session. Below is some Python code that provides a "scalemol" Chimera command. Make a directory chimera/share/scalemol in your Chimera distribution and put the code below in file chimera/share/scalemol/ChimeraExtension.py. Then start Chimera, open the cage PDB model, use menu entry Favorites/Command line, and type a command: scalemol 0 1.5 to make model number 0 bigger by a factor of 1.5. If you have more than one model open you can see the model numbers using Favorites / Model Panel, the model number is shown in the left hand column. Tom - ---- scalemol/ChimeraExtension.py code follows: # ----------------------------------------------------------------------------- # def scale_molecule(cmdname, args): from Midas.midas_text import error fields = args.split() try: model_num = int(fields[0]) factor = float(fields[1]) except: error('Syntax error: scalemol <model-number> <factor>') return import chimera mlist = chimera.openModels.list(id = model_num) if len(mlist) == 0: error('scalemol: No model number %d' % model_num) return for model in mlist: for a in model.atoms: x, y, z = a.coord().xyz.data() c = chimera.Coord() c.x, c.y, c.z = (factor*x, factor*y, factor*z) a.setCoord(c) # ----------------------------------------------------------------------------- # import Midas.midas_text Midas.midas_text.addCommand('scalemol', scale_molecule) ------- End of forwarded message -------

1 0

get to lighting adjustment
by jinghua＠ucsd.edu 26 Apr '05

26 Apr '05

to whom it may concern, How could I get to the adcanced feature of lighting adjustment? Can I add more lights with different directions? Thanks! Jinghua <<>><<>><<>><<>><<>><<>><<>><<>><<>><<>><<>><<>><<>><<>><<>><<>><<>>< Jinghua Tang, Ph.D. Phone: 858-534-5852(o) 4107 Natural Sciences Bldg, MC-0378 858-597-2056(h) Department of Chemistry & Biochemistry Fax: 858-534-5846 University of California, San Diego E-mail: jinghua(a)ucsd.edu La Jolla, CA 92093-0378 http://jinghua.ucsd.edu <<>><<>><<>><<>><<>><<>><<>><<>><<>><<>><<>><<>><<>><<>><<>><<>><<>><

2 1

Writing the selection
by Charles Moad 19 Apr '05

19 Apr '05

How can I write the current selection to a file from a script? "write sel filename.pdb" does not work. Thanks, Charlie

2 2

v1.2105 for amd64 (x86_64)
by Sabuj Pattanayek 18 Apr '05

18 Apr '05

Hi, I don't know if this has been asked before (couldn't find anything on searches) but will there be a native amd64/emt64 (x86_64) build of chimera v1.2105? Thanks, Sabuj Pattanayek

2 1

Problem with Large Molecules
by Private 14 Apr '05

14 Apr '05

Dear Chimera Team: I think your work on Chimera has been of very high quality. In fact, I've used it to produce print quality images for an upcoming book of mine. However, I've had some problems with displaying some large molecules, for example, 1AYM and 1P5Y. I use the PDB file for the molecule, but specifically the assumed biological model file, not the the asymmetric unit file. I've been able to open the file in programs like Deepview and Raswin, but I can't open the file in Chimera. I'm running Windows 98 with about 256MB of RAM, and what happens when I attempt to open the assumed biological model file Chimera runs for over an hour trying to open the file and then crashes with a page fault message. I certainly would like to use the image capabilities provided by Chimera, so can you help me with this? Or is this simply a limitation of Chimera?

2 3

Thanks for the movie recorder
by Ann Mullin 08 Apr '05

08 Apr '05

I just tried out the movie recorder and I am very pleased. Thanks very much to the programmers who contributed to the addition of this tool to my favorite molecular graphics program. Ann Ann Mullin Research Scientist Cell and Molecular Biology Dept. Tulane University New Orleans, LA 70118-5698 504-865-6742 (Ph) 504-865-6785 (FAX) amullin(a)tulane.edu

1 0

yet another snapshot
by Eric Pettersen 05 Apr '05

05 Apr '05

A new snapshot release (1.2106) is available for Windows only, which fixes several issues the 1.2105 release had on that platform, namely: Movie Recorder movie encoding now works documentation searching fixed unreadable highlighted text in certain widgets fixed Eric Pettersen UCSF Computer Graphics Lab pett(a)cgl.ucsf.edu http://www.cgl.ucsf.edu

1 0

how were the virus images generated?
by Thomas Goddard 05 Apr '05

05 Apr '05

Hi Dieter, To make virus capsid images in Chimera like those on the VIPERdb web site, http://viperdb.scripps.edu/ or like those on our web site http://www.cgl.ucsf.edu/Research/virus/ http://www.cgl.ucsf.edu/chimera/ImageGallery/ you use the Chimera Multiscale tool, menu entry Tools / Multiscale / Multiscale Models. I'm guessing you tried making solvent excluded molecular surfaces with menu entry Actions / Surface / Show. That makes much higher resolution surfaces and tends to crash for large molecules or complexes. (We are working on replacing that third party code.) If your virus capsid PDB file header contains sixty REMARK 350 BIOMT matrices then you can just press the "Make Models" button at the bottom of the Multiscale dialog. This uses the matrices to make sixty copies of the asymmetric unit. You don't need a file containing coordinates for the full capsid with this tool. If your virus capsid PDB doesn't have the BIOMT matrices, but uses the coordinate system defined by the VIPER site (eg a PDB downloaded from VIPER), then you can instead choose Multimer Type: Icosahedral Symmetry, VIPER Z(2)35X(2) from the menu at the bottom of the Multiscale dialog, and then press the "Make Models" button. Once you have displayed the capsid model, you can color, hide, or display capsomeres at atomic resolution or with ribbons using the other buttons in the Multiscale dialog. For the full details look at the Tools section of the Chimera User's guide for Multiscale. http://www.cgl.ucsf.edu/chimera/docs/ContributedSoftware/multiscale/framemu… You can show this documentation in a web browser by just pressing the Help button at the bottom of the Multiscale dialog. Let me know if you have additional questions, Tom > From: "Dieter Blaas" > To: goddard(a)cgl.ucsf.edu > Date: Tue, 05 Apr 2005 12:38:20 +0200 > Subject: how were the virus images generated? > > Dear Tom, > Vijay referred my question to you: As far as I > understand were the virus images in VIPER generated > with Chimera. I have tried hard to generate similar > surface renderings with this software on a win2k 2 GB > machine but Chimera always crashes upon trying to > make the surface! Are there any particular parameters > which must be set? What is the limit of atoms, > coordinates, surface resolution, RAM? Many thanks for > any hints. > > Regards, Dieter Blaas > ------------------------------------------------------------------------ > Dieter Blaas, > Medical University of Vienna, > Inst. Med. Biochem., Vienna Biocenter (VBC), > Dr. Bohr Gasse 9/3, > A-1030 Vienna, Austria, > ------------------------------------------------------------------------ >

1 0

Chimera-users April 2005