February 2011 - Chimera-users - RBVI Mailing Lists

Script for positioning particles according the coordinates.
by Alexander MYASNIKOV 08 Feb '11

08 Feb '11

Dear colleagues, I would like to fit about 300 particles inside of the map according to it coordinates (X,Y,Z) what I have found before. Is it possible to make this procedure automatically, such that program would load one particle, shift it according to its coordinates (change pixel size if necessary) and so on? Thank you in advance, Alexander

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findclash "batch" calculations
by Elaine Meng 07 Feb '11

07 Feb '11

On Feb 4, 2011, at 2:51 AM, Julien wrote: > Hi Elaine, > I would like to find clashes between a ligand and a protein. I have around 100 000 poses of this ligands. > The information to get the poses are at the moment saved in a pdb file. Indeed three pseudo atoms are used to place the ligand in the correct position using the command match. > > The workflow would be the followin: > open ligand > open protein > open pseudo.pdb > > match ligand position1 > findclash > match ligand position2 > ... > > First, this is very slow, even in batch mode. Maybe you know a better way to do that. > Second chimera does not open more than 9999 residues, the pseudo pdb have nearly 100 000 residues. Is there a way to get around that. > > I guess the routine findclash calculates all distances brutally and compare them to a threshold. > many greetings > Julien Hi Julien, Findclash does calculate distances between atom centers, but the cutoff parameter is compared to "overlap" between the VDW spheres -- in other words, smaller atoms must be closer together than larger atoms to be considered overlapping or clashing. The output information (optional) includes both the center-center distances and the overlaps, however. You can limit the calculation to only certain atoms. There are also options to control cutoff and other settings. Details are here: <http://www.cgl.ucsf.edu/chimera/docs/UsersGuide/midas/findclash.html> If you are really just using "findclash" without arguments, that would look at the whole structure and take more time than necessary. For example, if your ligand is model #0 and the protein model #1, one way to limit the calculation to only clashes between them and send info to the Reply Log is: findclash #0 test #1 log true Otherwise, I'm not an expert on any large-scale calculations or how you might optimize the procedure for large sets of atoms, so I'm CC-ing this question to the chimera-users list. (It is generally better to send Chimera questions to this list rather than to me personally.) The other users or developers may have good ideas. Best, Elaine ----- Elaine C. Meng, Ph.D. UCSF Computer Graphics Lab (Chimera team) and Babbitt Lab Department of Pharmaceutical Chemistry University of California, San Francisco

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Fixing registration for older versions of Chimera
by Eric Pettersen 07 Feb '11

07 Feb '11

Hi everyone, About 10 days ago I sent mail about upgrading to 1.5.2 to fix Chimera registration problems and promised a fix for older versions soon. That fix is now available from this page: http://www.cgl.ucsf.edu/chimera/fixreg/ It involves running a script on that page or, for the slightly paranoid cautious among us, downloading two files and putting them in your Chimera distribution manually. Thanks for your patience. --Eric Eric Pettersen UCSF Computer Graphics Lab http://www.cgl.ucsf.edu

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Rotamers
by Angelica Nakagawa Lima 04 Feb '11

04 Feb '11

Hi I can get the rotamers if I use the graphical version (when I click in tools -> Structure Editing -> rotamers). But I would like to do same thing with the comands. I used the comand swapaa (swapaa ile :10.a) and I write the pdb with the ile's rotamer (the most probable), however I would like to write the pdb file with the second most probable rotamer too. How do I do this? Thanks Angelica

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rotamers
by Ricardo Silva 04 Feb '11

04 Feb '11

I am using chimera program to view the rotamers list of pdb archive. I have proceeded from the following form: first I open an archive for chimera, later go to tools menu and alow: Structute Editing > Rotamer, after that i chose* rotamer type* and* rotamer library* then select aply and chimera display rotamers values and its respective probabilities. My objective is to save the rotamers list in an archive. Would like know how as can I make these procedures using the chimera commands. Thanks Ricardo

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surface hydrophobicity display
by Elaine Meng 03 Feb '11

03 Feb '11

Hi Sumitro, I did a little more digging for related information and thought I would share -- however, none of these methods are available in Chimera currently. Miguel Ortiz Lombardia has pointed out that the GRID program calculates a hydrophobic potential, and sent us the following links: <http://biop.ox.ac.uk/www/lj2000/noble/noble_02.html> <http://www.moldiscovery.com/docs/vsplus/grid.html> -- the following web server sounded promising, but apparently no longer exists: PLATINUM: a web tool for analysis of hydrophobic/hydrophilic organization of biomolecular complexes. Pyrkov TV, Chugunov AO, Krylov NA, Nolde DE, Efremov RG. Bioinformatics. 2009 May 1;25(9):1201-2. <http://www.ncbi.nlm.nih.gov/pubmed/19244385> -- the following paper discusses what surface properties of the receptor correlate well with the types of nearby ligand atoms. If I understood it correctly, they looked at how successfully Coulombic electrostatic potential and the gradient in that potential can be used to identify hydrophobic areas of surface (areas that bind hydrophobic atoms in the ligand). Both were somewhat successful, but even better was a simple definition of hydrophobic surface as the part of the surface that is not close to hydrogen-bonding groups. This paper is fairly old and the data set of ligand/receptor structures small. Definition and display of steric, hydrophobic, and hydrogen-bonding properties of ligand binding sites in proteins using Lee and Richards accessible surface: validation of a high-resolution graphical tool for drug design. Bohacek RS, McMartin C. J Med Chem. 1992 May 15;35(10):1671-84. <http://www.ncbi.nlm.nih.gov/pubmed/1588550> -- then there are some other complicated functions based on molecular fragments and distances among them and to the molecular surface: A new approach to analysis and display of local lipophilicity/hydrophilicity mapped on molecular surfaces. Heiden W, Moeckel G, Brickmann J. J Comput Aided Mol Des. 1993 Oct;7(5):503-14. Estimating and representing hydrophobicity potential Fauchere et al. Journal of Molecular Graphics Volume 6, Issue 4, December 1988, Pages 203-206 If I understood correctly, these have many parameters and the functional form is not simple. It would not be straightforward to put them into Chimera. Finally, I also saw that the program MDL Chime has something called hydrophobic potential display, but I couldn't find a description of how it really works -- it might just be coloring whole amino acids by hydrophobicity value like Chimera does now, or atoms based on element. Elaine ---------- Elaine C. Meng, Ph.D. UCSF Computer Graphics Lab (Chimera team) and Babbitt Lab Department of Pharmaceutical Chemistry University of California, San Francisco

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rotamers
by Ricardo Silva 02 Feb '11

02 Feb '11

Chimera can be used to get rotamers from a selected residue of a given structure of protein and show such rotamers in a specific archive. I would like to know how to do it using a script(line commands) Thanks Ricardo

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rotamers
by Ricardo Silva 02 Feb '11

02 Feb '11

I am working in the development of a program that I need the possible rotameros (of one the 5 possible rotamers) for a set of amino acids and I would like to know as chimera can make this using the command line. Debtor, Ricardo

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rotamers_library
by Ricardo Silva 01 Feb '11

01 Feb '11

I have a archive .pdb and I woul like to obtain rotamers library using command Thanks Ricardo

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Chimera-users February 2011