- Chimera-users - RBVI Mailing Lists

Collaboratory tool removed ?
by Aurelien Grosdidier 27 Mar '08

27 Mar '08

Hello, I recently noticed that the current production version of Chimera (v1 build 2470) does not have the "Collaboratory tool" anymore. I wanted to give it a try and I am quite disappointed. From a previous changelog (http://www.cgl.ucsf.edu/chimera/docs/relnotes/1.2417.html) I read that "Collaboratory removed (use version 1.2309 for this tool)". My question is: can we expect this feature to be back one day, or should I look for an alternative ? Thanks, Aurélien.

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Chimera
by Robert Hilton 27 Mar '08

27 Mar '08

When using Chimera, I want to be able to use XY translation. In the help menu, I found that if I hold down the middle mouse button, I can control XY translation. However, I have a mac, and so have no middle mouse button. How can I control XY translation using a mac? Thanks, Rob Hilton hiltonlds(a)gmail.com

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copy cmd in nogui script
by Nick Horelik 26 Mar '08

26 Mar '08

Hi, This (http://www.cgl.ucsf.edu/pipermail/chimera-users/2007-March/001396.html) answered most of my questions, but I have one more followup question. Is there any way for me to accept the POV-Ray Liscence in nogui mode? I don't have the capability to use the gui at this time. Thanks, Nick -- Tufts University 508.527.9625

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Re: [Chimera-users] using chimera on 3D EM map
by Tom Goddard 26 Mar '08

26 Mar '08

Hi Weimin, Thanks for explaining these problems. We intend to solve all of them (though it will take some time) and perhaps some already have solutions. 1) Volume eraser ball can't be made small enough. The ball can have any floating point radius value > 0. So you should be able to make it as small as you like. I've tried and had no trouble making it tiny. A radius value of 0 is not valid and the ball radius will be left at whatever it was prior to attempting to set it to zero. 2) There is no "undo" in volume eraser. Yes. This is a serious problem we plan on fixing. 3) No way to add density (as opposed to subtracting with volume eraser). I guess you mean you would like to use a 3d ball to mark the density you wish to keep instead of the density you want to erase. It might be easy to make a tool like this where you can paint the volume using a ball (like volume eraser). You could paint using one or more colors and then separate the different colored pieces into separate maps. The underlying code to do this is already in Chimera (color zone tool, and split map by color zone). It requires a way to place a marker that matches the painting ball -- basically just a "Color" button on the volume eraser dialog. Might be able to add this soon. I recently added plane by plane loop drawing for hand tracing surfaces that can be used with the new "mask" command to segment out the enclosed region (in current daily builds). But from what you say that is less useful in your high resolution case. 4) Statistical comparison of two maps. Chimera can report the correlation coefficient between two maps and it can optimize the position of one map within another. This tools was called "Fit Map in Map" in the current Chimera production release (version 1.2470) and is called "Fit in Map" (which also handles fitting models) in current Chimera daily builds. There is also a new option in "Fit in Map" that will update the correlation coefficient in real time as you move one map within the second map. Also there is a new "Fit in Map" option that will compute a simulated map from a PDB at a given resolution (like EMAN pdb2mrc) and will fit the simulated map and report its correlation in the experimental map. Are there other measures besides correlation coefficient that you want? From your example, maybe you want rotations in degrees between two different fits? Tom Weimin Wu wrote: > Dear Prof.: > > I am one postdoctoral in Prof. Wenjiang's group. We have employed > Chimera in our research and really appreciate it. However when our 3D > map goes beyond 5A (see Feb. 28, 2008 Nature paper) which enabled us > to see the boundaries among alpha helices and beta sheets, we meet > some problems in the segmentation which we do think you could help us > out. > > One problem is that the viewer eraser ball is too big even the radius > is set to zero. It prevented us from completely clearing the > neighboring signals. There is no undo option when using the eraser > function. Therefore we have to keep saving the intermediate maps. > > Another problem is that there is no 3D volume editor which can let us > add density in 3D EM map. Sometimes this is the most important for the > segmentation, because it is hard to tell which density should be > included if we go slice by slice, but it is much easier to tell > directly in 3D map with the stereo function. > > Another problem is that there is no statistical tool for analyzing the > slight difference between two 3D EM maps. Therefore it makes hard to > determine the fit quality of one map into the other, for example, when > fitting one subunit into the other, there is some conformation > difference between them, but we need quantitative values to evaluate > the difference and make a story. Something like in two PDBs, we can > fit one domain and check the difference of the other domain. > > If I don't explain the problems clearly, please let me know. Many thanks, > > weimin wu

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Re: [Chimera-users] [chimera-dev] fit map in map -- also fit a/pix at the same time ?
by Tom Goddard 26 Mar '08

26 Mar '08

Hi Stefan, Chimera cannot optimize the volume grid spacing when fitting a molecule model. I agree that would be useful. I'll add it to our requested features list. http://www.cgl.ucsf.edu/chimera/plans.html You can do this scale optimization by hand using the volume dialog Coordinates panel to change the voxel size (press the return key after you change the number), then press the Fit button on the Fit in Map dialog. With small scale changes the fit should converge each time and you can quickly try several different scales. The newer Chimera releases (Jan 31, 2008, 1.2492) available on the daily builds page can make a simulated map for your molecule at the desired resolution and report correlation coefficients which is probably better than average map values for this scale optimization. Tom

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Chimera_v1.2470
by Brittney L. Gurda 26 Mar '08

26 Mar '08

Hello, I have a general question about opening files in the new version. Upon opening my EM maps (in .pif format), my structure is in a solid box which makes viewing difficult. Has anyone encountered this problem before? The older version that I had (not sure which one) never had this issue. Currently I am converting the .pif to a .map file and that seems to work just fine, but I am still curious about where the box is coming from and how I can get rid of it...artificial unit cell perhaps? Thanks, Brittney L. Gurda

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pdb to density map function
by Jeff Triffo 25 Mar '08

25 Mar '08

hi, I think I recall seeing information about a pdb -> density map function (like an MRC density map). is this currently implemented/contained within Chimera? I can use an outside program to do this, but if it is already in Chimera I would prefer to do that. thanks, -Jeff

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Displaying volumes with negative densities
by Tom Goddard 24 Mar '08

24 Mar '08

Hi Julio, If you are creating volume contour surfaces where the objects of interest have more negative data values then you should turn off the "cap high values at box faces" option in the volume dialog surface and mesh options panel. Since you view these inverted density maps often you probably want to save that setting using volume dialog menu entry "Features / Save default dialog settings" so Chimera will use it in future sessions. Tom Dr .Julio Ortiz wrote: > Dear Thomas, > > I noticed that when displaying volumes as isosurfaces we can not > visualize negative densities. The volumes turns a solid cube bellow > cero. I can imagine that with volumes coming from some programs of > SPA like in EMAN, this is not a matter, because they use > protein=white. But we are always using protein=black. > > I wanted to ask you if there is a simple way to correct that, because > I love to use chimera for fast check of my volumes and it will be not > fun to change the contrast each time. > > Just for your info: the last version that works for me was: > chimera-1.2422-win32 > > Greetings, > Julio

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Principal axis of inertia
by Jean-Didier Maréchal 21 Mar '08

21 Mar '08

Hi everyone, I was wondering if there is a method available to calculate the principal axis of inertia of a protein (or a part of a protein) in chimera? If not what would be the easiest way to move forward? All the best, JD -- Dr. Jean-Didier Maréchal Professor Lector Computational Bioorganic and Bioinorganic Chemistry @Transmet Office C7/018 Edifici C.n. Campus de Bellaterra Departament de Química Universitat Autònoma de Barcelona 08193 Bellaterra, Catalunya, Spain Tel: (+34).935814936 Fax: (+34).935812920 e-mail: jeandidier.marechal(a)uab.es www: http://asklipio.qf.uab.es/cmc

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BILD object question
by William Jeffrey Triffo 21 Mar '08

21 Mar '08

hello, I have been writing simple .bild files for BILD objects (arrows, spheres) that I then load into Chimera. what would the commands be in a python script to generate a BILD model within the current session, so that I don't have to keep hand-writing and re-loading the .bild file (the contents of the .bild file are often outputted coordinates from such a script, that I then copy into a text file and load)? thanks, -Jeff

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turning off PipesAndPlanks or Axes
by Boaz Shaanan 21 Mar '08

21 Mar '08

Hi, How do I turn off PipesAndPlanks once they're depicted ? The same holds for Axes. (build 2492). Thanks, Boaz Boaz Shaanan, Ph.D. Dept. of Life Sciences Ben-Gurion University of the Negev Beer-Sheva 84105 Israel Phone: 972-8-647-2220 ; Fax: 646-1710 Skype: boaz.shaanan‎

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source headers, release
by Randy Heiland 20 Mar '08

20 Mar '08

Before I attempt to rebuild a plugin, can someone tell me if the 1.2349 headers that you currently provide: http://www.cgl.ucsf.edu/ chimera/sourcecode.html will play nice with the current, 1.2470, release? thanks, Randy

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problem with 17/03 build linux 64
by Jean-Didier Maréchal 19 Mar '08

19 Mar '08

Hi guys, thanks a lot for the different answers. I wanted to test Elaine's suggestion and I install the last linux 64 build. When running chimera I have: Traceback (most recent call last): File "/usr/local/chimera/share/__main__.py", line 65, in <module> value = chimeraInit.init(sys.argv) File "/usr/local/chimera/share/chimeraInit.py", line 304, in init from chimera import tkgui File "CHIMERA/share/chimera/tkgui.py", line 80, in <module> File "CHIMERA/share/chimera/printer.py", line 444, in <module> AttributeError: 'module' object has no attribute 'No' Some problem in my installation ? All the best JD El mié, 19-03-2008 a las 12:00 -0700, chimera-users-request(a)cgl.ucsf.edu escribió: > Send Chimera-users mailing list submissions to > chimera-users(a)cgl.ucsf.edu > > To subscribe or unsubscribe via the World Wide Web, visit > http://www.cgl.ucsf.edu/mailman/listinfo/chimera-users > or, via email, send a message with subject or body 'help' to > chimera-users-request(a)cgl.ucsf.edu > > You can reach the person managing the list at > chimera-users-owner(a)cgl.ucsf.edu > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Chimera-users digest..." > > > Today's Topics: > > 1. Re: Principal axis of inertia (Eric Pettersen) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Wed, 19 Mar 2008 11:47:51 -0700 > From: Eric Pettersen <pett(a)cgl.ucsf.edu> > Subject: Re: [Chimera-users] Principal axis of inertia > To: "'Chimera BB'" <chimera-users(a)cgl.ucsf.edu> > Message-ID: <DDE1C65B-AD42-48C1-9414-91625662D812(a)cgl.ucsf.edu> > Content-Type: text/plain; charset=ISO-8859-1; delsp=yes; format=flowed > > Just wondering why you weighted by atomic number rather than mass > (a.element.mass)? > > --Eric > > On Mar 19, 2008, at 11:42 AM, Tom Goddard wrote: > > > Hi JD, > > > > Attached is a script that computes the inertia axes of molecules. > > Open a molecule, then open the script. It will print the axes in > > the reply log and show an inertia ellipsoid. It is weighting the > > atoms by their atomic number, not by the average isotopic mass. > > Tested in Chimera 1.2498. Should work in older Chimera versions. > > > > Tom > > > > Jean-Didier Mar?chal wrote: > >> Hi everyone, > >> > >> I was wondering if there is a method available to calculate the > >> principal axis of inertia of a protein (or a part of a protein) in > >> chimera? > >> > >> If not what would be the easiest way to move forward? > >> > >> All the best, > >> > >> JD > >> > >> > > > > > > # > > ---------------------------------------------------------------------- > > ------- > > # Compute inertia tensor principle axes for molecule. > > # > > def inertia_ellipsoid(m): > > > > atoms = m.atoms > > n = len(atoms) > > from _multiscale import get_atom_coordinates > > xyz = get_atom_coordinates(atoms) > > anum = [a.element.number for a in atoms] > > from numpy import array, dot, outer, argsort, linalg > > wxyz = array(anum).reshape((n,1)) * xyz > > mass = sum(anum) > > > > c = wxyz.sum(axis = 0) / mass # Center of mass > > v33 = dot(xyz.transpose(), wxyz) / mass - outer(c,c) > > eval, evect = linalg.eigh(v33) > > > > # Sort by eigenvalue size. > > order = argsort(eval) > > seval = eval[order] > > sevect = evect[:,order] > > > > return sevect, seval, c > > > > # > > ---------------------------------------------------------------------- > > ------- > > # > > def ellipsoid_surface(center, axes, lengths, color = (.7,.7,.7,1)): > > > > from Icosahedron import icosahedron_triangulation > > varray, tarray = icosahedron_triangulation(subdivision_levels = 3, > > sphere_factor = 1.0) > > from numpy import dot, multiply > > es = dot(varray, axes) > > ee = multiply(es, lengths) > > ev = dot(ee, axes.transpose()) > > ev += center > > > > import _surface > > sm = _surface.SurfaceModel() > > sm.addPiece(ev, tarray, color) > > return sm > > > > # > > ---------------------------------------------------------------------- > > ------- > > # > > def show_ellipsoid(axes, d2, center, model): > > > > from math import sqrt > > d = [sqrt(e) for e in d2] > > sm = ellipsoid_surface(center, axes, d) > > sm.name = 'inertia ellipsoid for %s' % m.name > > from chimera import openModels as om > > om.add([sm], sameAs = model) > > > > # > > ---------------------------------------------------------------------- > > ------- > > # > > def print_axes(axes, d2, m): > > > > from math import sqrt > > paxes = ['\tv%d = %6.3f %6.3f %6.3f d%d = %6.3f' % > > (a+1, axes[a][0], axes[a][1], axes[a][2], a+1, sqrt(d2[a])) > > for a in range(3)] > > from chimera.replyobj import info > > info('Inertia axes for %s\n%s\n' % (m.name, '\n'.join(paxes))) > > from Accelerators.standard_accelerators import show_reply_log > > show_reply_log() > > > > # > > ---------------------------------------------------------------------- > > ------- > > # > > from chimera import openModels as om, Molecule > > mlist = om.list(modelTypes = [Molecule]) > > for m in mlist: > > axes, d2, center = inertia_ellipsoid(m) > > print_axes(axes, d2, m) > > show_ellipsoid(axes, d2, center, m) > > _______________________________________________ > > Chimera-users mailing list > > Chimera-users(a)cgl.ucsf.edu > > http://www.cgl.ucsf.edu/mailman/listinfo/chimera-users > > > > ------------------------------ > > _______________________________________________ > Chimera-users mailing list > Chimera-users(a)cgl.ucsf.edu > http://www.cgl.ucsf.edu/mailman/listinfo/chimera-users > > > End of Chimera-users Digest, Vol 59, Issue 18 > *********************************************

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Un-tile
by Jim Nettles 19 Mar '08

19 Mar '08

Thanks that is a useful function I hadn't explored. However, how to you un-tile to go back to a previously aligned system? Thanks, Jim > > Message: 4 > Date: Wed, 19 Mar 2008 16:53:11 +0530 > From: "Bharat Yadav" <bharatbioinformaticshau(a)gmail.com> > Subject: [Chimera-users] Requesting to solve my poblem > To: chimera-users(a)cgl.ucsf.edu > Message-ID: > <e162fe4e0803190423k5651193amf41e192251b613c3(a)mail.gmail.com> > Content-Type: text/plain; charset=ISO-8859-1 > > Hello Sir / Madam > > Good Evening > > My name is Bharat Yadav and I am perusing Master's Degree in > Bioinformatics from Chaudhary Charan Singh Haryana Agriculrual > University - Hisar (India). I am working here on Molecular Modeling. > With a long time I am using UCSF Chimera. It is the one of wonderful > Molecular visiualization software haivng some very peculear features. > Respected Sir / Madam, In my present work I am facing a bit problem. > Hoping form you to help regarding this. My problem is as follows. I > have generated five models of protein. when I open all these modles > these were overlapping each other. I want to view all these five > models in a single panel non overlapping. I mean I want to view these > 3D models in panel as follows > ----------------------------------------- > | | | > | | | > | Model 1 | Model 2 | > | | | > ----------------------------------------- > | | | > | | | > | Model 3 | Model 4 | > | | | > ----------------------------------------- > | | | > | | | > | Model 5 | Model 6 | > | | | > ----------------------------------------- > > Hope that you now easily understand what actually I want. Please Help > me regarding this and mail me its solution or steps or commands for > this task. Please free to ask any question. > > Thanks in anticipation > > Warm regards from Bharat Yadav > > > ------------------------------ > > Message: 5 > Date: Wed, 19 Mar 2008 10:11:52 -0700 > From: Elaine Meng <meng(a)cgl.ucsf.edu> > Subject: Re: [Chimera-users] Requesting to solve my poblem > To: "Bharat Yadav" <bharatbioinformaticshau(a)gmail.com> > Cc: chimera-users(a)cgl.ucsf.edu > Message-ID: <37BB555C-E967-43BB-B6EA-5CD8A75853FD(a)cgl.ucsf.edu> > Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed > > Hi Bharat, > > Thanks for your kind words! I think you just need to use "tile" in > the Model Panel. Open Model Panel (Favorites... Model Panel). In > there, choose all 5 models on the left side. Then, on the right, > change the menu from "frequently used" to "infrequently used" - now > there should be a "tile" button on the right - try using that. > > I hope this helps, > Elaine > ----- > Elaine C. Meng, Ph.D. meng(a)cgl.ucsf.edu > UCSF Computer Graphics Lab and Babbitt Lab > Department of Pharmaceutical Chemistry > University of California, San Francisco > http://www.cgl.ucsf.edu/home/meng/index.html > >

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Data of Slice display
by Jason 19 Mar '08

19 Mar '08

Hi all I am using slice display to plot the profile of density map. That is the function that I want to exam the profile of virus density map without spherical average. Where can I get the data of each dot of profile, so I can plot profile at Excel for further use. Thank you for your help Kind regards Jason Chen -- Open WebMail Project (http://openwebmail.org)

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Average slab thickness
by Tom Goddard 19 Mar '08

19 Mar '08

Hi Jeff, The Chimera mask command code can be adapted to calculate the average thickness of a slab defined by two surfaces. I've attached the adapted Python code. You select the surfaces then open the script and it reports the mean thickness, standard deviation of thickness, min/max thickness and number of thickness samples used. The script contains a projection axis which should be perpendicular to the slab and a grid step which defines the grid spacing. The thickness is measured on a grid perpendicular to the axis and only grid points where the projection axis intersects the surfaces at least twice are used. You have to edit the script (at the bottom) to set the projection axis and grid step to appropriate values. Those values could be automatically set using the Python code of the inertia ellipsoid script I gave you earlier. Tested in Chimera version 1.2498 on a spherical surface. Tom Jeff wrote: > hi Tom, > > I'd like to compute the 'average distance' between two surfaces to > calculate the width of a cellular compartment (have attached an image, > the two surfaces delineating the compartment are colored blue). > > one way that has been suggested to me is to calculate the volume > between the two surfaces, and then just divide by a mean path length > along one of the surfaces. I know that chimera has a volume > calculation tool for an isosurface, and was wondering if I could use > the surfaces you see to do a volume calculation (and, if so, how I > would go about capping those surfaces to create a closed surface). If > able to calculate the volume that way, I could just use the path > length of a contour (which I have) that generated one of the two > surfaces to derive the "average width". > # ----------------------------------------------------------------------------- # Script to calculate average thickness of a slab defined by surfaces. # Adapted from mask command code for Jeff Triffo, March 18, 2008. # # Adapted version of masked_volume() from depthmask.py. # # Only uses first two surface layers along projection axis. # def average_thickness(projection_axis = (0,0,1), grid_step = 1.0, surfaces = None): # Use selected surfaces if none are passed in. if surfaces is None: from Surface import selected_surface_pieces plist = selected_surface_pieces() from Mask.depthmask import surface_geometry surfaces = surface_geometry(plist, tf = None, pad = None) # Determine transform from vertex coordinates to depth array indices from Mask.depthmask import orthonormal_frame fx,fy,fz = orthonormal_frame(projection_axis) from numpy import array, float32, intc, zeros tf = array(((fx[0], fx[1], fx[2], 0), (fy[0], fy[1], fy[2], 0), (fz[0], fz[1], fz[2], 0)), float32) / grid_step # Transform vertices to depth array coordinates. zsurf = [] tcount = 0 for vertices, triangles in surfaces: varray = vertices.copy() from Mask.depthmask import apply_transform apply_transform(tf, varray) zsurf.append((varray, triangles)) tcount += len(triangles) if tcount == 0: return 0,0,0,0,0 from Mask.depthmask import bounding_box vmin, vmax = bounding_box(zsurf) voffset = -(vmin - 0.5) tf[:,3] += voffset from _contour import shift_vertices for varray, triangles in zsurf: shift_vertices(varray, voffset) from math import ceil, floor dxsize = int(ceil(vmax[0] - vmin[0] + 1)) dysize = int(ceil(vmax[1] - vmin[1] + 1)) # Create depth arrays depth = zeros((dysize,dxsize), float32) tnum = zeros((dysize,dxsize), intc) depth2 = zeros((dysize,dxsize), float32) tnum2 = zeros((dysize,dxsize), intc) # Copy volume to masked volume at masked depth intervals. max_depth = 1e37 depth.fill(max_depth) tnum.fill(-1) from Mask.depthmask import surfaces_z_depth any = surfaces_z_depth(zsurf, depth, tnum, None, None) if not any: return 0,0,0,0,0 depth2.fill(max_depth) tnum2.fill(-1) surfaces_z_depth(zsurf, depth2, tnum2, depth, tnum) # Find thicknesses at grid points that intercept surfaces twice. dlist = [] for i in range(dysize): for j in range(dxsize): if tnum[i,j] != -1 and tnum2[i,j] != -1: d = (depth2[i,j] - depth[i,j]) * grid_step dlist.append(d) if len(dlist) == 0: return 0,0,0,0,0 from numpy import mean, std return mean(dlist), std(dlist), min(dlist), max(dlist), len(dlist) # ----------------------------------------------------------------------------- # projection_axis = (0,0,1) grid_step = 1.0 m, sd, mn, mx, n = average_thickness(projection_axis, grid_step) print ('Slab thickness along axis %s sampled at grid spacing %.3g' % (str(projection_axis), grid_step)) print 'Mean %.5g, sdev %.5g, min %.5g, max %.5g, samples %d' % (m,sd,mn,mx,n) from Accelerators.standard_accelerators import show_reply_log show_reply_log()

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Requesting to solve my poblem
by Bharat Yadav 19 Mar '08

19 Mar '08

Hello Sir / Madam Good Evening My name is Bharat Yadav and I am perusing Master's Degree in Bioinformatics from Chaudhary Charan Singh Haryana Agriculrual University - Hisar (India). I am working here on Molecular Modeling. With a long time I am using UCSF Chimera. It is the one of wonderful Molecular visiualization software haivng some very peculear features. Respected Sir / Madam, In my present work I am facing a bit problem. Hoping form you to help regarding this. My problem is as follows. I have generated five models of protein. when I open all these modles these were overlapping each other. I want to view all these five models in a single panel non overlapping. I mean I want to view these 3D models in panel as follows ----------------------------------------- | | | | | | | Model 1 | Model 2 | | | | ----------------------------------------- | | | | | | | Model 3 | Model 4 | | | | ----------------------------------------- | | | | | | | Model 5 | Model 6 | | | | ----------------------------------------- Hope that you now easily understand what actually I want. Please Help me regarding this and mail me its solution or steps or commands for this task. Please free to ask any question. Thanks in anticipation Warm regards from Bharat Yadav

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interface residues
by Francesco Malatesta 17 Mar '08

17 Mar '08

Hello, could anyone help me out with this problem. I would like to exclusively colour interface residues in a dimeric protein represented as spheres or surface. Is this possible? Thank you very much Francesco Malatesta

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preferences - povray - keep input files doesn't
by Klaas Decanniere 17 Mar '08

17 Mar '08

For at least some versions of Chimera, the "keep pov-ray input files" option in the Favorites - Preferences- Pov-ray tab does not work ( .pov files are deleted after rendering during animation) This is true e.g for build 2491 2008/02/11 (Platform: linux2 windowing system x11). Is there a way to force this option? I would like to do some post processing on the .pov files before rendering. An option to generate an animation series .pov files without doing the actual rendering would be even better - how can I do that? Thanks for the help and kind regards, Klaas Decanniere

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segmentation fault - surface rendering
by Michael DiMattia 13 Mar '08

13 Mar '08

Hello, I am trying to surface render a few different proteins within the same Chimera session and I keep encountering a segmentation faullt. I imagine this is due to a memory limit being reached, although I do not know if it is a Chimera parameter that can be increased/overriden. Instead of having the different macromolecules in the same pdb, I have actually split it up into many pdbs and opened them one at a time, surface rendering one at a time. This worked for awhile but it seems I can't even get that far now. Any advice or tips on what I can do? I realize surface rendering is very computationally intensive but I would love to get this to work! Thanks Mike DiMattia

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[chimera-users]torsional angle
by 吴超 11 Mar '08

11 Mar '08

Hi, folks! I have a problem about the measurement of torsional angle. In the chimera users' guide about the command angle, as follows, it says that if I select the atoms simultaneously, the order information will get lost. How can I keep the order information since I need it to calculate the angle I want exactly? For example, in the following command I originally want to calculate the n-ca-c-n(182) dihedral, angle :181.a@n,ca,c:182.a@n but in fact what chimera gave me was may be c-ca-n-n(182). I want to calculate a lot of diheral information so I can not click one by one in the gui mode, I wonder is there any way that I can get what I want . Thanks! Usage: *angle* *atom1 atom2 atom3* [ *atom4* ] *Angle* reports the bond angle for three specified<http://www.cgl.ucsf.edu/chimera/1.2199/docs/UsersGuide/midas/atom_spec.html…>atoms or the dihedral angle for four specified<http://www.cgl.ucsf.edu/chimera/1.2199/docs/UsersGuide/midas/atom_spec.html…>atoms. The order of specification is important, but atoms need not be connected. The angle value in degrees is reported in the status line<http://www.cgl.ucsf.edu/chimera/1.2199/docs/UsersGuide/chimerawindow.html#s…>and *Reply Log*<http://www.cgl.ucsf.edu/chimera/1.2199/docs/UsersGuide/reply.html>. The atoms can be specified collectively using the word *selected*, *sel*, or *picked* if the current selection<http://www.cgl.ucsf.edu/chimera/1.2199/docs/UsersGuide/selection.html>contains only the three or four atoms of interest; the order in which the atoms were selected<http://www.cgl.ucsf.edu/chimera/1.2199/docs/UsersGuide/selection.html>(most likely picked<http://www.cgl.ucsf.edu/chimera/1.2199/docs/UsersGuide/selection.html#picks…>) is used. When order information is lacking (for example, the atoms were selected simultaneously), the angle actually measured may not be the one intended. There are no automatic updates if the angle changes. A new command must be issued to measure the changed angle. -- Chao Wu Currently: National Institute of Biological Sciences, Beijing Huang Niu's Lab http://www.nibs.ac.cn/ Tel: 80726688-8572 Address: Beijing ZhongGuanCun Life Science Park, NO.7 Science Park East Road, NIBS B427 Postcode: 102206 Life Science Honors Program, China Agricultural University PO.1055, NO.2 YuanMingYuan west road, Beingjing, 100094 P.R. China Tel: 86-10-62812484 E-mail: lynnwuchao(a)gmail.com

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pdb format and charges
by Terry Lang 06 Mar '08

06 Mar '08

Hey Everyone, I would like to use Chimera to write charges for a pdb file in the b-factor column. I feel like this is possible but couldn't quite figure out how to do it. Sincerely, Terry -- P. Therese Lang Post Doc Alber Lab, UC Berkeley

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one question about slicing
by Martin 06 Mar '08

06 Mar '08

Hi, I write in this mail to ask your great help on the slicing of MRC files. I want to slice a map in MRC format in half and save it as a new MRC file which only contains the remaining half map. However, it seems that the "Per-Model Clipping" function of Chimera can only work on the visualization mode, without connection to the "Save map as" function to attain a new map file. I am wodering if there is any other method to realize my intention. Thank you very much! Sincerely yours, Jian

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Unit cell coordinates, Python / Chimera
by Tom Goddard 05 Mar '08

05 Mar '08

Hi Rachel, Attached is Python code that prints the unit cell axes of open PDB models to the reply log. You open the PDB models, then open this script, and the results appear in the reply log (menu Favorites / Reply Log), for example: 1a0m.pdb unit cell axes a axis = 44.400 0.000 0.000 b axis = 0.000 44.400 0.000 c axis = 0.000 0.000 23.500 I figured out the needed Chimera calls by looking at the Chimera Python code for the Unit Cell tool located in your Chimera distribution in chimera/share/UnitCell/__init__.py and I homed in on the show_outline_cb() function to quickly figure out the attached code. On the Mac this code is in Chimera.app/Contents/Resources/share/UnitCell/__init__.py and to look inside the Chimera.app folder click on its icon with the ctrl key held and select "Show Package Contents". Tom > *From: *Rachel Karchin > *Date: *March 4, 2008 5:42:36 PM PST > > Me again. Is there a way to get the coordinates of the unit cell > vertices or the plane equation from Chimera running through a python > script? > > Tx!! > > -- rk # Get currently opened PDB models from chimera import openModels, Molecule mlist = openModels.list(modelTypes = [Molecule]) # Print crystal unit cell axes for each molecule. from PDBmatrices.crystal import crystal_parameters, unit_cell_axes for m in mlist: a, b, c, alpha, beta, gamma, space_group, zvalue = \ crystal_parameters(m.pdbHeaders) a_axis, b_axis, c_axis = unit_cell_axes(a, b, c, alpha, beta, gamma) print m.name, 'unit cell axes:' print ' a axis = %8.3f %8.3f %8.3f' % tuple(a_axis) print ' b axis = %8.3f %8.3f %8.3f' % tuple(b_axis) print ' c axis = %8.3f %8.3f %8.3f' % tuple(c_axis)

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Step through trajectory from command line?
by Kristina Furse 05 Mar '08

05 Mar '08

Hi- Can you advance a trajectory by one frame from the command line, or do you have to use the controls in the MD Movie panel? Thanks, Kristina -- Kristina Furse Postdoctoral Research Associate 262 Stepan Chemistry Hall Notre Dame, IN 46556 (574)631-3904

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