- Chimera-users - RBVI Mailing Lists

coloring seperate domains
by Anindito Sen 09 Oct '08

09 Oct '08

HI all I was wondering how to color the c and n terminals of the crystal structure docked in the density map different. Thanks Dr. Anindito Sen (Ph.D) Research Associate , Dept. of Biochemistry and Molecular Genetics University of Virginia Box 800733 Charlottesville, VA 22908

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"extended" Zone specifier
by Francesco Pietra 08 Oct '08

08 Oct '08

What I would like to do is a global search of which residues of model #0 are within a certain distance from which residues of model #1. Where "model" stands for a protein in both cases. That would save time in simulations of docking (not using DOCK) between proteins. I can locate with Chimera key residues, but their number is large. Thanks francesco pietra

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incorporate chimera commands into a shell script
by shyamala 07 Oct '08

07 Oct '08

Hi, I am fairly new to Chimera. I am trying to calculate the RMSD of the heavy atoms across two different ligand (small molecule) coordinate files. I don't need a least square fit performed, hence using rmsd as opposed to match. I have to do this comparison for around 200 docked conformations against the native ligand conformation, hence I am thinking shell script that can call chimera to execute this command is the way to go. I am not sure how to first select the two small molecules and then use the rmsd command when I start chimera in nogui mode. Any help, examples, pointers will be very much appreciated. Thanks a lot, Shyamala

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Re: [Chimera-users] symmetric fitting
by Tom Goddard 07 Oct '08

07 Oct '08

Hi Sudheer, This means your GroEL map does not have the cylinder axis along z. When you press the Orient button in the volume dialog you can see the orientation, the screen horizontal axis is x, the screen vertical axis is y, and in/out of the screen is z. I've attached a Python script that can produce the symmetry matrices for different cylinder axes. You run it by opening it in Chimera and the output is seen in the Reply Log (Favorites menu). You'll need to edit the script to use the correct axis. Tom skmolugu(a)miners.utep.edu wrote: > Hi Tom, > I have used the matrix file you have gave me and could succesfully generate the coordinates file. After saving the pdb file with the new coordinates, I reopened the saved pdb file that has 14 subunits and it is turns out to be perpendicular to map that has been used. How can I avoid this problem? > thank you very much for your time, > sincerely, > sudheer. > ---------------------------------------- > >> Date: Mon, 6 Oct 2008 12:06:32 -0700 >> From: goddard(a)cgl.ucsf.edu >> To: skmolugu(a)miners.utep.edu >> CC: chimera-users(a)cgl.ucsf.edu >> Subject: Re: [Chimera-users] symmetric fitting >> >> Hi Sudheer, >> >> Figuring out the symmetry matrices for using the symmetric fitting >> capability >> >> http://www.cgl.ucsf.edu/chimera/tutorials/volumetour/volumetour.html#symcop… >> >> requires some work. First note that the symmetry matrices you want are >> those that transform (rotate and shift) the volume data to an identical >> configuration. >> >> Your case is 2 stacked 7-mer rings. Assuming the z axis is the >> symmetry axis of the map (need to set origin so the center of the >> cylinder is at xyz = 0,0,0 in the volume dialog Coordinates panel) you >> could just compute the needed rotation matrices >> >> cos(a), sin(a), 0 >> -sin(a), cos(a), 0 >> 0, 0, 1 >> >> Could write a script (python script attached) or use a calculator. Also >> you want to flip around x axis by 180 degrees to get 7 more rotations >> with the two 7-member rings exchanged. With that approach I get the >> following lines to add to the PDB file: >> >> REMARK 350 BIOMT1 0 1.000000 0.000000 0.000000 0.000000 >> REMARK 350 BIOMT2 0 -0.000000 1.000000 0.000000 0.000000 >> REMARK 350 BIOMT3 0 0.000000 0.000000 1.000000 0.000000 >> REMARK 350 BIOMT1 1 0.623490 0.781831 0.000000 0.000000 >> REMARK 350 BIOMT2 1 -0.781831 0.623490 0.000000 0.000000 >> REMARK 350 BIOMT3 1 0.000000 0.000000 1.000000 0.000000 >> REMARK 350 BIOMT1 2 -0.222521 0.974928 0.000000 0.000000 >> REMARK 350 BIOMT2 2 -0.974928 -0.222521 0.000000 0.000000 >> REMARK 350 BIOMT3 2 0.000000 0.000000 1.000000 0.000000 >> REMARK 350 BIOMT1 3 -0.900969 0.433884 0.000000 0.000000 >> REMARK 350 BIOMT2 3 -0.433884 -0.900969 0.000000 0.000000 >> REMARK 350 BIOMT3 3 0.000000 0.000000 1.000000 0.000000 >> REMARK 350 BIOMT1 4 -0.900969 -0.433884 0.000000 0.000000 >> REMARK 350 BIOMT2 4 0.433884 -0.900969 0.000000 0.000000 >> REMARK 350 BIOMT3 4 0.000000 0.000000 1.000000 0.000000 >> REMARK 350 BIOMT1 5 -0.222521 -0.974928 0.000000 0.000000 >> REMARK 350 BIOMT2 5 0.974928 -0.222521 0.000000 0.000000 >> REMARK 350 BIOMT3 5 0.000000 0.000000 1.000000 0.000000 >> REMARK 350 BIOMT1 6 0.623490 -0.781831 0.000000 0.000000 >> REMARK 350 BIOMT2 6 0.781831 0.623490 0.000000 0.000000 >> REMARK 350 BIOMT3 6 0.000000 0.000000 1.000000 0.000000 >> REMARK 350 BIOMT1 7 1.000000 -0.000000 0.000000 0.000000 >> REMARK 350 BIOMT2 7 -0.000000 -1.000000 0.000000 0.000000 >> REMARK 350 BIOMT3 7 0.000000 0.000000 -1.000000 0.000000 >> REMARK 350 BIOMT1 8 0.623490 -0.781831 0.000000 0.000000 >> REMARK 350 BIOMT2 8 -0.781831 -0.623490 0.000000 0.000000 >> REMARK 350 BIOMT3 8 0.000000 0.000000 -1.000000 0.000000 >> REMARK 350 BIOMT1 9 -0.222521 -0.974928 0.000000 0.000000 >> REMARK 350 BIOMT2 9 -0.974928 0.222521 0.000000 0.000000 >> REMARK 350 BIOMT3 9 0.000000 0.000000 -1.000000 0.000000 >> REMARK 350 BIOMT1 10 -0.900969 -0.433884 0.000000 0.000000 >> REMARK 350 BIOMT2 10 -0.433884 0.900969 0.000000 0.000000 >> REMARK 350 BIOMT3 10 0.000000 0.000000 -1.000000 0.000000 >> REMARK 350 BIOMT1 11 -0.900969 0.433884 0.000000 0.000000 >> REMARK 350 BIOMT2 11 0.433884 0.900969 0.000000 0.000000 >> REMARK 350 BIOMT3 11 0.000000 0.000000 -1.000000 0.000000 >> REMARK 350 BIOMT1 12 -0.222521 0.974928 0.000000 0.000000 >> REMARK 350 BIOMT2 12 0.974928 0.222521 0.000000 0.000000 >> REMARK 350 BIOMT3 12 0.000000 0.000000 -1.000000 0.000000 >> REMARK 350 BIOMT1 13 0.623490 0.781831 0.000000 0.000000 >> REMARK 350 BIOMT2 13 0.781831 -0.623490 0.000000 0.000000 >> REMARK 350 BIOMT3 13 0.000000 0.000000 -1.000000 0.000000 >> >> If your map origin is not the center of symmetry or an x-axis flip is >> not a symmetry then these matrices won't work. You can try to set the >> correct origin -- the right value can be found with some tricky use of >> the output of the Fit in Map tool, fitting one copy of the map into >> another copy. Or you could fit one copy of the map to another and use >> the matrixget command to output that symmetry matrix to a file, then do >> that for all symmetries to create the needed matrix text. >> >> As you see this process has not yet been made easy. >> >> Tom >> >> >> >> >> >> skmolugu(a)miners.utep.edu wrote: >> >>> HI, >>> In the symmetric fitting model session that explains about the symmetry generation, i did not understand the method to generate the matrix. I am working on a chaperonin protein called GroEL. It has 14 subunits with seven fold symmetry. can you please explain me how to update the pdb and the matrix values that i need to put in the pdb file. >>> thankyou, >>> sudheer >>> _______________________________________________ >>> Chimera-users mailing list >>> Chimera-users(a)cgl.ucsf.edu >>> http://www.cgl.ucsf.edu/mailman/listinfo/chimera-users >>> # Chimera script to print symmetry matrices for GroEL 14-mer. format = '''REMARK 350 BIOMT1 %3d %10.6f %10.6f %10.6f %10.6f REMARK 350 BIOMT2 %3d %10.6f %10.6f %10.6f %10.6f REMARK 350 BIOMT3 %3d %10.6f %10.6f %10.6f %10.6f''' axis = (0,0,1) import Matrix as m flip = m.rotation_from_axis_angle((1,0,0), 180) # 180 degree rotation about x. flip = [r + (0,) for r in flip] # Zero translation. for i in range(14): a = 360.0*i/7.0 t = m.rotation_from_axis_angle(axis, a) # Rotation by i/7 turn about z. t = [r + (0,) for r in t] # Zero translation. if i >= 7: t = m.multiply_matrices(flip, t) # Exchange top and bottom ring. print format % ((i,) + t[0] + (i,) + t[1] + (i,) + t[2])

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obtaining rotation angles
by Jaap Brink 06 Oct '08

06 Oct '08

Hi, I'm trying to figure out how I can obtain angles from chimera. I have a 3D object that I have to rotate in order to see certain features. I'd like to know those angles. Is there is a way to get this info? Thanks in advance, Jaap Brink

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Re: [Chimera-users] symmetric fitting
by skmolugu＠miners.utep.edu 06 Oct '08

06 Oct '08

HI, In the symmetric fitting model session that explains about the symmetry generation, i did not understand the method to generate the matrix. I am working on a chaperonin protein called GroEL. It has 14 subunits with seven fold symmetry. can you please explain me how to update the pdb and the matrix values that i need to put in the pdb file. thankyou, sudheer

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Failure of Surface Display
by Charles Letner, Ph.D. 04 Oct '08

04 Oct '08

Hello, I am trying to display a surface using the Actions > Surface>Show menu. The surface is not displaying and the following error is in the reply: C:\Program Files (x86)\Chimera\bin\mscalc.exe 1.400000 2.000000 1 Calculation of some surface components failed (code 5). Falling back to single-component calculation. C:\Program Files (x86)\Chimera\bin\mscalc.exe 1.400000 2.000000 0 Surface calculation failed, mscalc returned code 5 I am using Chimera version: production version 1 build 2540 2008/07/09 Platform is Windows Vista 64 bit. The file I am working with contains 2 subunits. If I split the two subunits into separate files and open individually in the same session, the surfaces display without any issue. I am trying to show the surface of the two subunits associated, not the surface of each individual subunit. Any help will be appreciated. Cheers, Chuck

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Re: [Chimera-users] Failure of Surface Display - Additional Info
by Charles Letner, Ph.D. 04 Oct '08

04 Oct '08

I just installed the latest daily build (1.2562) and get the same error. ----- Original Message ----- From: Charles Letner, Ph.D. To: chimera-users(a)cgl.ucsf.edu Sent: Saturday, October 04, 2008 11:59 AM Subject: Failure of Surface Display Hello, I am trying to display a surface using the Actions > Surface>Show menu. The surface is not displaying and the following error is in the reply: C:\Program Files (x86)\Chimera\bin\mscalc.exe 1.400000 2.000000 1 Calculation of some surface components failed (code 5). Falling back to single-component calculation. C:\Program Files (x86)\Chimera\bin\mscalc.exe 1.400000 2.000000 0 Surface calculation failed, mscalc returned code 5 I am using Chimera version: production version 1 build 2540 2008/07/09 Platform is Windows Vista 64 bit. The file I am working with contains 2 subunits. If I split the two subunits into separate files and open individually in the same session, the surfaces display without any issue. I am trying to show the surface of the two subunits associated, not the surface of each individual subunit. Any help will be appreciated. Cheers, Chuck

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volume viewer question
by Ben Keshet 03 Oct '08

03 Oct '08

Hi Chimera fans, Can someone please help me understand how to read and look at .nrg files (generated by Grid)? I am interested in visually exploring the electrostatic potential around a protein. Specifically, when I opened it, everything was in one color, with negatively charged regions being darker, but I would imagine that positively charged regions should have a different color. On a related note - is there a tool to calculate and view the electric field lines around a molecule / protein? Thanks for your time and help, Ben

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Poor performance with 30 molecules
by Thomas Goddard 03 Oct '08

03 Oct '08

Hi Ben, The main trick to improve efficiency in Chimera with many copies of a molecule is to use only the C-alpha coordinates. This is usually acceptable with working with EM data resolutions. You create a PDB file with only the CA atoms (can use "select @CA" command and Chimera File / Save PDB...) reducing the total number of atoms by 10x or more. Chimera is a very memory inefficient with molecules taking about 2 Kbytes per atom. This is about 10x worse than PyMol and VMD. You start feeling this at about 100,000 atoms and up and run into real trouble around 500,000 atoms if you are using 32-bit Chimera (no 64-bit available on Windows or Mac) because you run out of address space. The ability to rotate the models depends on rendering speed. Above 100,000 atoms only "wire" style will be fast and you must have a graphics driver installed (not Mesa on Linux). With a 4 year old graphics card (Radeon 9800 Pro) I get 10 frames per second with 200,000 atoms. With a newer card you should handle 500,000 atoms in wire at reasonable frame rates. Chimera session files include all the PDB atom coordinates. Chimera has no way to show 30 copies of a PDB file at different positions without having 30 independent copies of the data, except using surfaces with the multiscale tool. The multiscale tool does not interoperate easily with fitting in maps. Tom Elaine Meng wrote: > Begin forwarded message: > >> From: Benoit Zuber <bzuber(a)mrc-lmb.cam.ac.uk> >> Date: October 2, 2008 10:24:34 AM PDT >> To: Elaine Meng <meng(a)cgl.ucsf.edu> >> Subject: Re: [Chimera-users] volume viewer window >> >> Hi Elaine, >> I just aligned a tiny subtomogram to a model with a lot of different >> parameter, which generated many volumes. Then I wanted to visualize >> all the results at once. Since each volume was tiny, chimera was not >> struggling, it was fine :-) >> >> However that reminds me another issue about memory I had sometime ago. >> I have a tomogram into which I have fitted many copies (more than 30) >> of the same pdb file. There are two problems: 1) compiling the session >> file takes ages (around 10 minutes I would say). Opening the compiled >> session file takes more than 1 minute. >> 2) if I display all the copies of the pdb, everything is very slow (I >> mean if I want to move anything in space, it takes very long). If I >> display only a few copies (plus 1 or two slices through the tomogram), >> then it works fast. >> >> For the 2nd problem, there is maybe no easy solution to speed up the >> calcultations, but for the first one, since we are dealing with copies >> of a single pdb, wouldn't it be possible to make the process faster? I >> reckon that the coordinates of each atom of each copy of the pdb are >> saved. Would there be a way to save only one copy and transformation >> matrix for every copy? Would it speed up file saving-compiling-opening >> operations? >> >> Cheers, >> Ben > > Hi Ben, > I know Tom Goddard has made many recent improvements in Volume Viewer > memory usage and speed, but it sounds like your main issue is many > atomic structures rather than lots of volume data. > > If the PDB copies are identical except in transformation, there is some > capability in Multiscale Models to only store one copy of the > coordinates and show the others as low-res surfaces. However, as soon > as you try to show any more detailed display such as ribbons or atoms > and bonds, the full coordinates for that copy are loaded. If you > actually want to view ribbons/atoms/bonds for each copy, I don't know of > any mechanism to save memory. Also, to use Multiscale Models in this > way, you would have to generate an input PDB file with matrices > describing all of the transformations, which sounds difficult. Yet > another way to handle multiple coordinate sets for the same atoms is as > a trajectory. However, then you can only view one member of ensemble > (one "time step" from the trajectory) at a time, so that also would not > solve your problem. > > I CC'd Tom and Eric in case they have any ideas. > Best, > Elaine > >

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