March 2022 - ChimeraX-users - RBVI Mailing Lists

A question about model position matrix
by Zheng Ruan 31 Mar '22

31 Mar '22

Dear ChimeraX users, I'm trying to understand the model position matrix. According to the documentation, "Each matrix is reported as 12 comma-separated numbers, corresponding to a 3x3 rotation matrix and a translation vector in the fourth column. Ordering is row-by-row, such that the translation vector is given as the fourth, eighth, and twelfth numbers." When I load a model into ChimeraX and use "view matrix" command to check the model position, I got "#1,1,0,0,0,0,1,0,0,0,0,1,0,#1.1,1,0,0,0,0,1,0,0,0,0,1,0". The rotation matrix for #1 is an identity matrix with translation vector to be 0 for all directions. However, if I rotate the model using the command "turn z 90 models #1" and then check the model position using "view matrix", I got something like "#1,1.1102e-16,-1,0,689.33,1,1.1102e-16,0,-1.9358,0,0,1,0,#1.1,1,0,0,0,0,1,0,0,0,0,1,0". The translation vector for #1 becomes (689.33, -1.9358, 0). Since I only applied a simple rotation of the model along z-axis, why the translation vector becomes non-zero in this case? I hope to have a better understanding of how ChimeraX handles the model position matrix to describe model positions. Thank you so much! Best, Zheng

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Bundle Module Import
by Zeng, Katie 31 Mar '22

31 Mar '22

Hi all, I am currently working on a membrane builder bundle called AmberLipidBundle. I have folder './src/ui' (containing several .py files, e.g. lipid_form.py) and I import it inside .py files with the line 'from AmberLipidBundle.ui.lipid_form import xxx'. I have been testing the bundle using the command 'devel build [path]' and everything works fine. But when I switch to the command 'devel install [path]', I get an error: chimerax.core.toolshed.ToolshedError: start_tool() failed for tool Membrane Builder in bundle AmberLipidBundle: No module named 'AmberLipidBundle.ui' Do you have any idea how to fix this? Thank you so much for your help! Best Regards, Katie

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get current clipping plane positions
by Pranav Shah 31 Mar '22

31 Mar '22

Hi Elaine and Co., Is there a way to read the current clipping plane positions in chimerax? Best, Pranav -- Pranav Shah Postdoctoral Research Fellow. Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK

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get current clipping positions
by Pranav Shah 30 Mar '22

30 Mar '22

Hi Elaine and Co., Is there a way to read the current clipping plane positions in chimerax? Best, Pranav -- Pranav Shah Postdoctoral Research Fellow. Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK

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Selection of the organic ligand
by Enrico Martinez 30 Mar '22

30 Mar '22

Dear ChimeraX users! Normally I use the selection name "ligand" to select all atoms of the organic ligand. For example: define centroid ligand name lig_com sometimes depending on the pdb file, this command also selects one residue (located in the pdb file just near the ligand), considering it also as a part of the ligand.. May I use another selection to explicitly exclude all 20 natural amino-acids from the ligand selection? Many thanks in advance! Enrico

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Re: [chimerax-users] [Chimera-users] using old cmd files in chimerax
by Elaine Meng 29 Mar '22

29 Mar '22

Hi Bryan, If I understand correctly, by "old" you mean works in Chimera... and would like to know how to get to the same end results except in ChimeraX, so I also CC'd chimerax-users(a)cgl.ucsf.edu. Since ChimeraX and Chimera commands do have differences, you cannot simply open Chimera command files in ChimeraX. Possible routes to getting what you want: (1) text-edit the cmd file to change Chimera commands to ChimeraX commands, change the filename suffix of that plain-text file to .cxc and then open it in ChimeraX. ChimeraX does have the capability to read ResMap maps and then use the values to color a surface, so this is a viable route. The downside is that it requires knowing or looking up the differences in the commands. Many commands are highly similar so it wouldn't necessarily be as bad as it sounds, however. You can open both the original map and the ResMap map files with ChimeraX command "open", control which is shown as a surface with the ChimeraX Volume Viewer tool or "volume" command, and color the surface by the values of the other map using "color sample". See ChimeraX User Guide: <https://rbvi.ucsf.edu/chimerax/docs/user/commands/open.html> <https://rbvi.ucsf.edu/chimerax/docs/user/tools/volumeviewer.html> <https://rbvi.ucsf.edu/chimerax/docs/user/commands/volume.html> <https://rbvi.ucsf.edu/chimerax/docs/user/commands/color.html#map> (2) or simply dispense with trying to use a command script and instead use ChimeraX tools and/or commands interactively. You can use ChimeraX menu: File... Open to open the maps (aka volume data), and there is a Surface Color tool (same function as "color sample" command): <https://rbvi.ucsf.edu/chimerax/docs/user/tools/surfacecolor.html> (3) in the more general case of Chimera command scripts involving atomic data, you can open/run the script in Chimera, export a session from Chimera as a ChimeraX python file (Chimera menu: File... Export Scene or Chimera command "export") and then open that file in ChimeraX to regenerate the session contents. <https://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/export.html> However, this Chimera->ChimeraX export feature does not (yet) cover maps, map isosurfaces, and a few other things. I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Department of Pharmaceutical Chemistry University of California, San Francisco > On Mar 28, 2022, at 12:01 PM, Hansen, Bryan (NIH/NIAID) [E] via Chimera-users <chimera-users(a)cgl.ucsf.edu> wrote: > > Hi, > How do I used/open old cmd scripts I have or outputs from things like resmap in chimerax? >

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addh
by Voss Jonathan Mark 28 Mar '22

28 Mar '22

Hello, I would like to protonate ASP, GLU, and HIS side chains throughout a model. I'm a little confused about the syntax of the useAspName, useGluName, etc. option. I've looked around but haven't found any examples. Could you provide one? Furthermore, once a side chain is protonated, will ISOLDE recognize that site as being charged? Or does this need to be specified somehow? Best -Jon

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Question about using ChimeraX
by 令怡 25 Mar '22

25 Mar '22

Dear developers, Hello! I recently encountered some problems when using ChimeraX. When displaying the structure with cartoon, some helix is displayed as loop (Fig A). How to force it to be displayed as helix? I checked the User Guide and used the command "setattr sel residues is_helix true" for the selected amino acids, but only some amino acids can be displayed as helix (Fig B). Is that need to change ss_ id? I have tried, but it didn't work. I will appreciate it if you could answer my question. Looking forward to your reply! Best Regards Lingyi

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Analysis of the protein-ligand docking results with the X-ray data
by Enrico Martinez 25 Mar '22

25 Mar '22

Dear ChimeraX users! First, I very much appreciate the support of the Chimera team related to my questions! I have another question regarding analysis of the protein ligand interactions in the docking poses saved in multi-model format. I need to find a possibility (e.g. via some script that could be executed in the chimeraX) to compare each docking pose with the X-ray structure (loaded as the separate model) in order to select automatically the model (= docking solution) which may fit better to the X-ray structure. The problem is that the ligand used in the docking is not the same as in the X-ray structure (although they are quite similar in the functional groups). Assuming that the both pdbs ((docking poses, and X-ray structure)) have been superimposed (based on the protein atoms) how could I automatically switch to the model (in the docking ensemble) that has the closest position of the ligand as in the X-ray structure? Here is the example of the workflow: open docking_ensemble.pdb open xray.pdb # fit X-ray structure to the first docking solution based on the protein atoms match #2 to #1.1 # compare each docking pose (ligand with X-ray and determine which model has the most similarity to it # determine the model #1.X which would have closest similarity to the X-ray structure # close all the models, with the exemption of the model #1.X close ~ #1.X I would be grateful for any suggestions for possible algorithms! With kind regards, Enrico

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Problem with ChimeraX
by Gawargi, Flobater I 23 Mar '22

23 Mar '22

Hi, I am a new Chimerax user and I have encountered a problem that I hope you can help me fix. I installed 1.4 version and it shows "Startup Messages notes available bundle cache has not been initialized yet Updating list of available bundles failed: Internal Server Error” all I am trying to do is use alpha fold to predict structure of 2 proteins separated by comma. And it shows this error "Missing or invalid "sequences" argument: Sequences argument "cvfpfvflgkqyssctsdgrrdgrlwcattsnfdtdkkwgfcpdqgyslflvaahefghalgldhssvpealmyplysylegfplnkddidgiqylygrgskpdprppattttepqptapptmcptipptayptvgptvgptgapspgptsspspgptgapspgptapptagsseasteslspadnpcnvdvfdaiaeiqgalhffkdgwywkflnhrgsplqgpfltartw" is not a chain specifier, alignment id, UniProt id, or sequence characters” I am using an M1 MacBook, but I have also tried it on windows running windows 10 and got the same issue. I would appreciate your input to fix this issue. Thank you, Flobater Gawargi The information in this e-mail may be privileged and confidential, intended only for the use of the addressee(s) above. Any unauthorized use or disclosure of this information is prohibited. If you have received this e-mail by mistake, please delete it and immediately contact the sender.

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