- Chimera-users - RBVI Mailing Lists

how to get nonbonded distance and torsion angle list
by Prem Prakash Pathak 28 Sep '06

28 Sep '06

Hi! I am using the chimera for the visualizing protien form *.pdb file. I wanted to get the nonbonded distance , *.upl file and angle constraint files. Would you please help me in solving the problem. PremPrakash

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"longbond" in scripts
by Eric Pettersen 26 Sep '06

26 Sep '06

We've made some improvements to the "longbond" command (breaks non- physical bonds that show missing structure segments) which are not backward compatible with the previous version. We are wondering if anyone makes any significant use of the longbond command in scripts. If you do, we would consider making a new command with the improved behavior and leaving the longbond command unchanged for backwards compatibility. So speak up if this affects you. --Eric Eric Pettersen UCSF Computer Graphics Lab pett(a)cgl.ucsf.edu http://www.cgl.ucsf.edu

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Connolly surface and Triangulation
by Nihshanka Debroy 25 Sep '06

25 Sep '06

Hi, Not sure if this went the first time, so sending it again: ----------------------------------------------------------------------------------------------- I have been using Chimera to generate the Connolly surface for several different proteins and saving the surface information in X3D format. I was wondering what algorithms are used in the Connolly surface generation. Is it the same approach that Michael Connolly had come up with in his 1983 paper on Analytical Molecular Surface Calculation, or is it a variation of that algorithm? Also, when the surface information is saved by Chimera in X3D, it breaks the surface into triangular faces. I noticed that the coordinates of the points comprising the triangles are completely different from the atomic coordinates. I am interested in learning more about how the triangulation is created. If you could direct me to a link or paper that would help me better understand the algorithms involved in these two processes, that would be great! Thanks. Sincerely, Nihshanka

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chimera ubuntu/debian package?
by Javier Díez 25 Sep '06

25 Sep '06

Hy: Is there a chimera version for ubuntu or debian? I would like to add the url to my sources.list if it exits. Thank you any way. Javi

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Re: [Chimera-users] Map Oddities
by Thomas Goddard 22 Sep '06

22 Sep '06

Hi Albion, When you are running Chimera and it opens a Python code file with suffix .py and there is an older byte compiled version of the same file with suffix .pyc then Python automatically recompiles the .py file and you should see that the date on the .pyc file is updated. You never need to compile Python files by hand. Here are 3 ideas about how to make some programs that read MRC maps establish equivalent map positions. As I mentioned in my previous email some programs may fail with certain maps to associate the x,y,z axes with the correct data axes. And some may ignore all header info about positioning. So there are alot of different cases. I'm only going to make suggestions for the simple problems. One idea is to have Chimera print out the difference between the origin that a crystallography program would use versus the MRC 2000 origin. You could insert a little code in the Chimera mrc_format.py file to print this difference for MRC 2000 files. Specifically after the line self.data_origin = (v['xorigin'], v['yorigin'], v['zorigin']) add lines # Print difference between crystal and mrc 2000 origins ncs_nrs_nss = v['ncstart'], v['nrstart'], v['nsstart'] nxs, nys, nzs = ncs_nrs_nss[xa], ncs_nrs_nss[ya], ncs_nrs_nss[za] from VolumeData.griddata import scale_and_skew x0,y0,z0 = scale_and_skew((nxs,nys,nzs), self.data_step, self.cell_angles) print 'Origin difference ', self.name, '=', print x0 - v['xorigin'], y0 - v['yorigin'], z0 - v['zorigin'] The origin difference will be printed to the Chimera reply log and you can somehow apply it in other programs. A second idea is to try to modify the MRC 2000 map header so that the crystal origin is the same as the xorigin, yorigin, zorigin header values. This is generally not possible since the former uses integers while the latter uses float values. But if you don't care where the origin is as long as all programs agree, you might adjust xorigin, yorigin and zorigin to match the crystal origin. You would need some simple program to modify the map header. A third approach is to modify Chimera mrc_format.py so it never uses the MRC 2000 xorigin, yorigin, zorigin. If Chimera always uses the crystal origin that would probably more often agree with other software packages. I would recommend against this approach. You will later install a new version of Chimera without the modification and your fit PDB models will no longer align with their maps and you will probably forget why and scream. Tom > From: Albion Baucom <baucom(a)msg.ucsf.edu> > Subject: Re: [Chimera-users] Map Oddities > Date: Fri, 22 Sep 2006 17:12:51 -0700 > To: Thomas Goddard <goddard(a)cgl.ucsf.edu> > > Hi Tom, > Im going to take this off list since my inquiries get more specific > now, but you are welcome to post this back to list if you think it is > within the scope of the Chimera Users list. > > So, you were right. There is indeed a X, Y and Z origin field in the > map header. Thanks for pointing that out and giving me the code to > print those values to the reply log. > > A quick question regarding my modification to the mrc_format.py. I > don't know Python very well yet, and am wondering what happens when I > modified the source code. The modifications worked of course, but > Chimera did not recompile the code into a .pyc file. When are > the .pyc files accessed? > > OK, back to the original question :) > > So, offhand, could you suggest a fix for me so that other programs > that use the "other" origin can interpret the data the same as > Chimera? Naturally what is going to have to happen is I will have to > translate the PDB file a set distance based on the discrepancy > between the origin conventions. I would like to do this translation > as accurately as possible. > > What I noticed from an empirical re-docking of the PDB file into the > density in another program was it had to be moved approximately ~116A > in all 3 axes. This appears to be close to the following calculation > (for the x axis in this case) > > ( | xorg | - xlen) + (xlen/2) > > where xorg (-224) is the MRC2000 origin, and xlen (213.423) is the > xtal origin. In this case this comes out to be > > (224.000 - 213.423) + (xlen/2) = 117.289 > > Applying this to the model as a translation in all 3 axes looks > almost exactly like what I see in Chimera. > > Does this make any sense? This is all I could come up with that gave > an answer close to my empirical docking translation numbers. > > Thanks Tom. I really appreciate your help. > > Albion

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Map Oddities
by Albion Baucom 22 Sep '06

22 Sep '06

Hi, I am trying to work out how maps are handled in various graphics programs so I can easily move between programs and expect to see the same thing in each session. Unfortunately at the moment that isn't working so well, and I would like to resolve this issue. Basically I have a situation where I have a PDB model and a CCP4 format EM density map in Chimera that are docked. When I open the exact same map and model in other programs such as O or Pymol, the map and the model are no longer in agreement. What I have noticed is that if I draw the unit cell for the map (P1 symmetry since this is an EM reconstruction), in Chimera, the model and map live in the center of the unit cell and are docked. If I draw the unit cell for O or Pymol, the map lives at the origin of the unit cell, at (0,0,0), which is in the corner, and model is outside of the unit cell offset by what appears to be some arbitrary translation (I have tried using half the unit cell dimensions as a translation, but that unfortunately gets me _very_ close to being correctly docked in the map, but off by some 10A). It appears Chimera is handling the map and model differently than the other packages and I am trying to get an idea of what happens when this map is loaded. I am including a listing of the map header from MAPMAN below. Thanks! Albion Grid = 96 96 96 Origin = -48 -48 -48 Extent = 96 96 96 Cell = 213.423 213.423 213.423 90.000 90.000 90.000 UVW = 1 2 3 Spcgrp = 1 Nr of points = 884736 Density min = -6.915E-01 Max = 2.397E+00 Average = 7.247E-11 Sigma = 2.290E-01 Variance = 5.243E-02 Mappage Prod= 8.257E+01 Plus = 57 Dyn. range = -6.903E-01 To = 2.398E+00 Cell vol. = 9.721E+06 Voxel vol. = 1.099E+01 Grid vol. = 9.721E+06 %Cell vol. = 100.00 Origin frac = -0.50000 -0.50000 -0.50000 Origin Cart = -106.712 -106.712 -106.712 Top frac = 0.48958 0.48958 0.48958 Top Cart = 104.488 104.488 104.488 Spacing = 2.223 2.223 2.223 Top = 47 47 47 Changes = F

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Movement Mouse Mode Extension
by Jared Godar 22 Sep '06

22 Sep '06

I have installed the Movement Mouse Mode Extension, but I get the following error whenever I try to select anything other than the 'Normal' movement mode on the drop-down menu. ImportError: cannot import name functionCallables (see reply log for Python traceback info) Any insight on how I can get this feature to work for me? Thanks, Jared (Log info below) Traceback (most recent call last): File "C:\Program Files\Chimera\share\__main__.py", line 59, in ? value = chimeraInit.init(sys.argv) File "C:\Program Files\Chimera\share\chimeraInit.py", line 308, in init tkgui.eventLoop() File "C:\Program Files\Chimera\share\chimera\tkgui.py", line 2757, in eventLoop app.mainloop() File "C:\Program Files\Chimera\bin\lib\lib-tk\Tkinter.py", line 965, in mainloop self.tk.mainloop(n) File "C:\Program Files\Chimera\bin\lib\site-packages\Pmw\Pmw_1_2\lib\PmwBase.py", line 1747, in __call__ return apply(self.func, args) File "C:\Program Files\Chimera\share\CGLtk\Hybrid.py", line 170, in <lambda> set_variable_cb = lambda v=self.variable, n=name: v.set(n) File "C:\Program Files\Chimera\share\CGLtk\Hybrid.py", line 780, in set self.tk_variable.set(value) File "C:\Program Files\Chimera\bin\lib\lib-tk\Tkinter.py", line 191, in set return self._tk.globalsetvar(self._name, value) File "C:\Program Files\Chimera\bin\lib\site-packages\Pmw\Pmw_1_2\lib\PmwBase.py", line 1751, in __call__ _reporterror(self.func, args) File "C:\Program Files\Chimera\bin\lib\site-packages\Pmw\Pmw_1_2\lib\PmwBase.py", line 1814, in _reporterror displayerror(msg) File "C:\Program Files\Chimera\bin\lib\site-packages\Pmw\Pmw_1_2\lib\PmwBase.py", line 1377, in displayerror _errorReportFile.write(text + '\n') File "C:\Program Files\Chimera\bin\lib\site-packages\Pmw\Pmw_1_2\lib\PmwBase.py", line 1747, in __call__ return apply(self.func, args) File "C:\Program Files\Chimera\share\CGLtk\Hybrid.py", line 832, in cb callback() File "C:\Program Files\Chimera\share\CGLtk\Hybrid.py", line 800, in tk_variable_changed_cb cb() File "C:\Program Files\Chimera\share\MoveSelection\gui.py", line 64, in mode_changed_cb move.set_mouse_mode(mmap[self.mode.get()]) File "C:\Program Files\Chimera\share\MoveSelection\move.py", line 569, in set_mouse_mode m = mover(create = True) File "C:\Program Files\Chimera\share\MoveSelection\move.py", line 598, in mover the_mover = Selection_Mover() File "C:\Program Files\Chimera\share\MoveSelection\move.py", line 36, in __init__ self.original_move_callbacks = self.wrap_mouse_modes() File "C:\Program Files\Chimera\share\MoveSelection\move.py", line 42, in wrap_mouse_modes from chimera.mousemodes import addFunction, functionCallables ImportError: cannot import name functionCallables -- Jared A. Godar Graduate Student: Stewart Lab Vanderbilt University Medical Center Molecular Physiology & Biophysics Dept. Light Hall 708 Work: 615.322.7898 Fax: 615.322.7236

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Connolly surface and Triangulation
by Nihshanka Debroy 21 Sep '06

21 Sep '06

Hi, I have been using Chimera to generate the Connolly surface for several different proteins and saving the surface information in X3D format. I was wondering what algorithms are used in the Connolly surface generation. Is it the same approach that Michael Connolly had come up with in his 1983 paper on Analytical Molecular Surface Calculation, or is it a variation of his algorithm? Also, when the surface information is saved by Chimera, it breaks the surface into triangular faces. I noticed that the coordinates of the points comprising the triangles are completely different from the atomic coordinates. I am interested in learning more about how Chimera creates the triangulation. If you could direct me to a link or paper that would help me better understand the algorithms involved in these two processes, that would be great! Thanks, Nihshanka

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AMBER netCDF trajectory
by Mingfeng Yang 20 Sep '06

20 Sep '06

Dear Chimera developers, The latest release of AMBER supports netCDF format trajectory. Is there any plan for Chimera to support AMBER's new format? Best, Mingfeng

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Chimera secondary-school use
by Thomas Goddard 19 Sep '06

19 Sep '06

Follow up on "[Chimera-users] first time use of chimera". ------------------ From: "Rich Kaufman" <richkaufmanpv(a)hotmail.com> To: goddard(a)cgl.ucsf.edu Subject: Chimera, afterthought Date: Tue, 19 Sep 2006 11:38:26 -0500 Dear Tom, Just to mention a few more details, I am trying to use electron density maps we generated in the lab using a Spider processing of cryo-EM photos .I will be downloading PDB's from the RCSB to dock with these. After properly hand docking the PDB, I will then load the density map and the hand-aligned PDB into a Normal Mode Flexible Fitting package ( NMFF ) for fine-tuning of the fit, to give a higher resolution picture of the electron density map. I've been working on this project for about three months. I had never heard of any of these things prior to that. It's been an amazing learning curve for me....quite interesting. Sincerely, Rich Kaufman, ( background....mainly physics; teacher of high school chemistry and physics ) P.S. One goal of this project is to enable me to use these techniques at the secondary education level. I don't know if that's doable....suggestions welcomed. --------------------- Date: Tue, 19 Sep 2006 10:00:38 -0700 (PDT) From: Thomas Goddard <goddard(a)cgl.ucsf.edu> To: richkaufmanpv(a)hotmail.com Subject: Re: Chimera, afterthought Hi Rich, Oh! I sent my previous email before I read this one about what you are actually doing. You're doing some fancy stuff. If you hand-align a PDB model in the SPIDER map you can then do a local position optimization within Chimera using menu entry Tools / Volume Data / Fit Models in Maps This moves the model using a rigid rotation and translation to maximize the map values at selected atom positions. Here's a page describing how to use it: http://www.cgl.ucsf.edu/chimera/tutorials/volumetour/volumetour.html#fitmod… The bottom of the following tutorial also gives step by step instructions for placing a PDB model in a map: http://www.cgl.ucsf.edu/Outreach/Workshops/UCSF-Fall-2005/07-VolumeData/tut… In fact, most of the tutorials on the following page do this kind of fitting: http://www.cgl.ucsf.edu/chimera/tutorials/tutorials.html The normal mode fitting you will do is fancier, allowing the model to deform to fit into the map. The following page explains alot of the Chimera features for working with density maps. http://www.cgl.ucsf.edu/chimera/tutorials/volumetour/volumetour.html The myosin animation on the following web page shows fitting a model into a map: http://www.cgl.ucsf.edu/chimera/animations/animations.html Finally, here are some databases that show some cryo-EM maps of viruses and other systems. http://viperdb.scripps.edu/tnumlist.php?N=all http://www.ebi.ac.uk/msd-srv/emsearch/AccEMServ?criterion=Retrieve+All&valu… I'm sure this is more than you wanted to know! Tom

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