- Chimera-users - RBVI Mailing Lists

chimera scalability on irix
by tyrrell t 04 Nov '13

04 Nov '13

I couldn't find any information on the subject, and have no hardware to test at the moment, but for a future deployment I need to work with IRIX systems, and I was wondering if chimera is coded to take advantage of multiple MIPS CPUs, or is it strictly a CPU-bound application? ie: would it run better on a dual-cpu octane system at 600mhz, or a 700mhz uni-processor fuel system? ( or something along this line )

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calculate axes from centroids
by Elaine Meng 04 Nov '13

04 Nov '13

On Nov 3, 2013, at 7:49 PM, Lili Peng <lilipeng(a)gmail.com> wrote: > Hi Elaine, > I've inquired you in the past regarding defining angles and planes in UCSF Chimera. > Do you know if there's a way to define an axis through two centroids, or through the center-of-mass of a residue and the centroid of a subunit, some combination like that? > Thank you, > Lili > Hi Lili, Currently, axes (and planes and centroids) can only be calculated from sets of atoms, not centroids. However, it can done in current Chimera by defining centroids, adding fake atoms at their positions, and using those atoms to define axes. You can specify whether each centroid calculation is mass-weighted (center of mass) or not (default, center of geometry). (a) use Axes/Planes/Centroids (or command "define") to define the desired centroids (b) look in Reply Log for the coordinates of each centroid ( c) add atoms: Tools… Structure Editing… Build Structure, Start Structure section, use settings to add atom with specific x,y,z coordinates to the existing model (the one whose atoms you used to define centroid) (d) use new atoms to define axis <http://www.rbvi.ucsf.edu/chimera/docs/ContributedSoftware/structuremeas/str…> <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/define.html> <http://www.rbvi.ucsf.edu/chimera/docs/ContributedSoftware/editing/editing.h…> There is also a "measure center" command that will automatically create a fake atom (option "mark true"), so you could use that instead for steps a-c, but it always does mass-weighting. For non-mass-weighted centroids, you would need to use the full process outlined above. <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/measure.html#center> I hope this helps. Sorry it is not as simple as it should be. 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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Fitting models into density - meaning of values
by Jessica Holien 30 Oct '13

30 Oct '13

I have been using Chimera to fit some homology models into the EM density (23A resolution) of a large complex. Although by eye it looks good I am trying to work out if statistically it is good. Can anyone tell me what is a good "Average Map Value" and what is a bad one? Thanks

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Coloring distance lines between atoms
by Tom Goddard 30 Oct '13

30 Oct '13

Hi Damien, Here is a Chimera Python script colordist.py that lets you color distance lines between atoms based on how long the distance is. The colors update as you move one model relative to another. After showing some distances, for instance with the "distance" command you would use command runscript colordist.py 8.5 green red to color the distance lines less than 8.5 Angstroms green, and longer ones red. The script needs to be in the directory you started Chimera in (e.g. on Linux), or you can specify a full path to the script "runscript /Users/Smith/colordist.py …", or use the Chimera "cd" command to change to the directory containing the script. You can select specific distance lines to color with the mouse and use runscript colordist.py 8.5 green red sel You can stop the color updating using runscript colordist.py or for just selected distance lines runscript colordist.py sel Tom On Oct 24, 2013, at 3:13 AM, Damien Larivière wrote: > Hi Tom, > > So, here is a reminder for the script we talked about. > > The idea is as follows: > > Once I have loaded several proteins in Chimera, once I have calculated distances between residue pairs that are displayed in the distance popup window, once I have displayed visually the distance as a colored stick pseudobond, then I would like a switch of the pseudobond color to occur when the distance is higher than a given value as I'm moving the proteins. > So, in my current manual modeling, I'm calculating a total of 24 distances between 5 proteins, I ask Chimera to display 24 pseudobond, most of them are initially let'say red, I load the script after having editing it with the distances and the associated maximal values, I move the proteins and the pseudobond color turn from red to yellow when the distance get lower than the maximal value defined for this distance in the script. And inversely, a pseudobond turns to red from yellow when it gets higher than a maximum distance. > > Let me know if you need more explanations. > > Many thanks for your help, > > Damien >

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color a small molecule in a .mol2 file by red to blue gradient of the partial charges
by Francois Berenger 30 Oct '13

30 Oct '13

Is it possible to do this in Chimera? I'd like a white background too. Thanks a lot, F.

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how to make the background of Chimera-generated images transparent
by Gea-Ny Tseng/FS/VCU 30 Oct '13

30 Oct '13

Dear Chimera developers and users: I would like to know how to make the background of Chimera-generated images transparent. I used to be able to do this with an older version of Chimera. But with Chimera 1.8, I could not figure out how to do this. There are options in the 'Color/Background' to adjust 'Opacity', which to me means that I could make the background transparent by using 'zero'. But this did not happen. Could you please advise? Thank you. Gea-Ny Tseng, PhD Dept of Physiology & Biophysics Virginia Commonwealth University

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Symmetry generation question
by Bala subramanian 29 Oct '13

29 Oct '13

Hello, 1) I have modelled one chain of a multimer. Since this is a modelled structure I dnt have any symmetry information in my pdb. In such case, how can I generate the symmetry related copies. Say I want to apply a fivefold symmetry along z-axis, how can I achieve it ? 2) I used a template structure from PDB to model my structure. What is the correct way to apply the symmetry of existing pdb model to my modeled chain. I tried this as follows, I opened my model as #0 and then the template pdb structure #1 and tried the following sym command and obtained an error as '#0 has no biological unit info.' sym #0 #1 Thanks, Bala -- C. Balasubramanian

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coloring plane by ESP
by Elaine Meng 29 Oct '13

29 Oct '13

Hi Marek, Just thought I'd mention that in Chimera you can color a plane that is in any orientation by the values in an ESP map. Unfortunately it doesn't work with the planes from Axes/Planes/Centroids, but you can create a rectangular plane with specified height and width with command "shape rectangle". Then you can open the molecule and the ESP map, activate/deactivate models (freeze/unfreeze them) and use the mouse to position the rectangle however you like in relationship to the molecule. Then you can use the "Surface Color" tool (aka Electrostatic Surface Coloring) to color the rectangle by the ESP map values. If you didn't already have an ESP map, you could use the PQR and APBS tools in Chimera to calculate one with APBS, or use the Coulombic Surface Coloring tool with option to "Compute grid" (i.e. make ESP map). Attached image is for 3eeb chain B, ESP map file 3eebB.phi ( available from link near bottom of the Surface Properties image tutorial <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/tutorials/surfprop.html> ), and rectangle created with command: shape rectangle height 50 width 50 widthdiv 100 heightdiv 100 center protein It shows the area of strong positive potential near where the highly negatively charged ligand binds. 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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no moleculr dispay with version 1.8
by Robert Wohlhueter 28 Oct '13

28 Oct '13

I have chimera-1.5.3 running on my Linux-AMD64 Ubuntu (12.10) computer. It works fine in every respect. Recently I installed version 1.8, with runs, but with one fatal flaw. By "runs", I mean the chimera screen comes up, the menus display. If I load (say, a pdb file), it seems to be there in the sense, for example, that I can open and view its sequence. BUT the molecule display window is absolutely blank (black). I suspect it has either to do with my python installation, or with my NVIDIA graphics driver. But whatever the problem, it effects only v. 1.8, not v. 1.5.3. For NVIDIA driver I'm using version 310.14. For python, I understand chimera uses 2.7. My python executable is indeed set as version 2.7.3 (that is, `python --version1 returns 2.7.3), though I have version 3 installed, and it could be used, if needed. I'm not all so clear on how envars PYTHONHOME and PYTHONPATH may or may not effect chimera. Of course, the easy way out is to stick with chimera-1.5.3 -- but one likes to stay up-to-date. Thanks in advance for any profound wisdom. Bob Wohlhueter

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Need help with fit into segment function
by Michael Matho 28 Oct '13

28 Oct '13

Hello, I have an EM map segmented in 5 segments I need to fit 5 molecules into. I'm trying to select a specific segment in order to fit each molecule individually, one after the other. After reading the tutorial, I still cannot figure out how to select only one segment of the map: If I try selecting from "Render/select by attribute" and choose "Segmentation regions" (and I do have the 5 segments ready), only the full map shows up, not the segments! In the "fit to segment" window, I select the molecule to fit and click on Fit... then there's a bug. I'd appreciate your help on how to finalize my fit. Thanks, Michael H. Matho, Ph.D. | Research Associate | Department of Cell Biology La Jolla Institute for Allergy and Immunology 9420 Athena Circle | La Jolla, CA, 92037 Tel: (858) 752-6631 | mmatho(a)liai.org

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