February 2010 - Chimera-users - RBVI Mailing Lists

Mac 64-bit Chimera for large data sets
by Tom Goddard 02 Feb '10

02 Feb '10

A 64-bit Mac Chimera daily build is now available for Mac OS 10.6. It will not run on Mac OS 10.5. http://www.cgl.ucsf.edu/chimera/download.html#daily If you work with EM maps larger than 1 Gbyte or molecular models of several hundred thousand atoms the larger addressable memory in the 64-bit version will help avoid out-of-memory errors and crashes. The 32-bit Mac Chimera versions can only address 4 Gbytes of memory and because libraries, stack and other uses of memory the practical working data size limit for 32-bit versions of Chimera is about 1 Gbyte. You should have more than 4 Gbytes of memory installed in order to benefit from the 64-bit version. The 64-bit Mac Chimera is in early testing so will have more bugs than usual. I've tested the 64-bit Mac Chimera running Gaussian filtering on a 2048 by 2048 by 800 map requiring about 3.2 Gbytes for the floating point result and 0.8 Gbytes for the original map. This worked correctly (took about 3 minutes on a machine with 6 Gbytes of memory) but failed with 32-bit Mac Chimera. We are also working on a 64-bit Windows Chimera that will work with Windows 7. This may be available within a month if no serious obstacles are encountered. A 64-bit Linux Chimera has been available for a few years. Tom

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alter volume data with python
by Michael Zimmermann 02 Feb '10

02 Feb '10

Dear Chimera users, I cannot find a way to search the chimera-users archive, so I appologize if this has been asked already. I wish to alter some volume data in specific ways; delete (zero out) all volume values that do not meet certain density criteria. The following code modifies the matrix values, but I can't figure out how to update the map that is being displayed in the volume viewer. I would like to be able to do something like: opened[0].full_matrix = H Then I would only see the swath that I "selected" with the following code. # ------------------------------------------------------------------------ source = '1R0A_antigen_6A_8s_0.425f_inv.mrc' opened = chimera.openModels.open(source) em = opened[0] H = em.full_matrix() s = H.shape for k in range(0,s[2]-1): for i in range(0,s[0]-1): for j in range(0,s[1]-1): if(H[i,j,k] >= -.28) and (H[i,j,k] <= -0.001): H[i,j,k] = H[i,j,k]+1 else: H[i,j,k] = 0 # ------------------------------------------------------------------------ Thank you, -- Michael Zimmermann Ph.D. student in Bioinformatics and Computational Biology Department of Biochemistry, Biophysics and Molecular Biology Iowa State University

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SDF Partial Charges
by Nancy 02 Feb '10

02 Feb '10

Hello, I am performing protein-ligand docking simulations, and the preferred ligand input file format is Mol2. I obtained some of my ligand structures from PubChem in SDF format, and I noticed that the SDF files contain partial charges ("PUBCHEM_MMFF94_PARTIAL_CHARGES"). Is there a way to preserve the charges in Chimera when converting to Mol2 file format? Thanks in advance. Nancy

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Converting SDF to Mol2: Errors
by Nancy 01 Feb '10

01 Feb '10

Hi All, When I convert an SDF file to Mol2 format using UCSF Chimera, I noticed that some valence errors were introduced. I can correct these errors for individual molecules, but doing so for large sets becomes cumbersome; is there any solution to this problem? Thanks in advance. Nancy

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Re: [Chimera-users] [Chimera] #8137: undesirable window placement (was: Chimera bug report submission)
by Eric Pettersen 01 Feb '10

01 Feb '10

Guy Nimrod wrote: > When I do an action that opens a new window (e.g. ‘file’ -> ‘save > session as’ or ‘file’-> ‘fetch by ID’), it seems that the new window > is located in a random position. Sometimes it is out of the borders > of the screen which is very problematic. Hi Guy, I think the new window-placement behavior is an improvement for most people. Nonetheless, it seems to be a problem for you so I've changed it into a preference (with the new behavior as the default). Starting with tomorrow's daily build there will be a preference in the General category called "Try to avoid placing dialogs over main window" which you can change to "false". Unfortunately the daily build for Windows hasn't been working lately, so it may be a few days before you can get a version with this preference available... --Eric Eric Pettersen UCSF Computer Graphics Lab http://www.cgl.ucsf.edu

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Chimera-users February 2010