November 2022 - ChimeraX-users - RBVI Mailing Lists

Change luminance in color palette
by Scott, Brandon L. 07 Nov '22

07 Nov '22

I am coloring surfaces using palettes (purples or a custom green-white-magenta). These both have a single luminance value, is it possible to generate a color palette that also has changing luminance. The ideal palette would be green -> white -> magenta along the color axis, and 0 - > 255 scaling the luminance of the rgb. We would effectively have a color bar matrix that goes from dark green to black to dark magenta if the values are low and bright green to white to bright magenta if the values are high. Thanks for your insights! -Brandon Brandon Scott, PhD CZI Imaging Scientist, Assistant Professor Nanoscience & Biomedical Engineering South Dakota Mines EEP 229 501 E. Saint Joseph St., Rapid City, SD 57701 724.510.1253 | Brandon.Scott(a)sdsmt.edu<mailto:Brandon.Scott@sdsmt.edu> [South Dakota Mines]<https://www.sdsmt.edu/>

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Create command for subunit model
by tim smith 06 Nov '22

06 Nov '22

Hi All, I would like to create a separate subunit model in chimeraX like create command in Pymol. In my PDB model, 3 subunits are present, I want to make each subunit as a model for representation. Thank you and best regards Tim

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Applying symmetry operations to generate an oligomeric model
by Robert Harkness 05 Nov '22

05 Nov '22

Hello, I am trying to generate a model of an oligomeric protein cage that consists of 4 trimers and has tetrahedral symmetry. I am using the asymmetric unit model consisting of one monomer (#0) and a density map (#1) as a starting point. My strategy has been to take the asymmetric unit and fit it into a portion of the map corresponding to one of the monomers within one of the trimer faces of the tetrahedron. Then I generate a copy of that asymmetric unit (#2) and fit it into the map for an adjacent protomer within the same trimer face. This results in the two asymmetric unit models being rotated 120 degrees relative to one another and part of the same trimer. Then I use the measure rotation command to measure the rotation of the second asymmetric unit relative to the first, giving me a rotation matrix and axis parameters. I then do sym #0 (first asymmetric unit) group t,z3 axis <axis from measure rotation> center <axis points from measure rotation> coordinateSystem #1 (the density map) And this generates the right looking trimers, so the 3-fold axis appears to be correct, but the center is off such that only one of the four trimers matches the density map and is placed at the top of the tetrahedron, while the other 3 trimers are off into the void of the scene but placed at the other 3 vertices. I am not sure how to appropriately define the center. My feeling is that it should be the center of the map, taken from the measure center #1 command, but implementing those numbers in sym doesn’t work either. Any thoughts on how these center coordinates are defined/should be measured, or if there is a better approach for doing this would be awesome! Best, Rob

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Create subunit model
by tim smith 05 Nov '22

05 Nov '22

Hi All, I would like to create a separate subunit model in chimeraX like create command in Pymol. In my PDB model, 3 subunits are present, I want to make each subunit as a model for representation. Thank you and best regards Tim

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Re: [chimerax-users] [Chimera-users] Jagged edges in chimera X
by Elaine Meng 04 Nov '22

04 Nov '22

Hi Prathvi, For ChimeraX questions, you may want to use the other mailing list, chimerax-users(a)cgl.ucsf.edu CC'd here. As per this recent post, ChimeraX does not have multisampling, but if you are saving an image you can use supersampling: <https://www.rbvi.ucsf.edu/pipermail/chimerax-users/2022-September/004310.ht…> ChimeraX also has a "graphics quality" command to increase the number of facets used to draw atoms, bonds, and cartoons (ribbons), although I don't know if that is going to help your issue very much: <https://rbvi.ucsf.edu/chimerax/docs/user/commands/graphics.html#quality> I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Department of Pharmaceutical Chemistry University of California, San Francisco > On Nov 3, 2022, at 4:59 AM, Prathvi Singh via Chimera-users <chimera-users(a)cgl.ucsf.edu> wrote: > > Hello Elaine, > > Is there a way to smoothen the jagged edges seen around ribbons and sheets in ChimeraX? > The jagged edges can be removed in UCSF chimera by setting the subdivision value to 20 and enabling multisampling but I do not see these features in chimeraX. > > -- > Prathvi Singh, > Research Fellow, > Department of Biological Sciences & Bioengineering, > Indian Institute of Technology, Kanpur-208016 > _______________________________________________ > Chimera-users mailing list: Chimera-users(a)cgl.ucsf.edu > Manage subscription: https://www.rbvi.ucsf.edu/mailman/listinfo/chimera-users

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How to discover hydrophobic between two chains
by McClean, Phillip 03 Nov '22

03 Nov '22

Hi Everyone, I ran AF2 multimer and have a two-chain complex. I ran the mlp command on the two chains separately and together. The two chains seem to interact via hydrophobic residues where chain B fits into a pocket on chain C. Here are the chain residues: /b:72-124 /c:1-190 Is there any way to determine which residues (hydrophobic) in each of these two regions are interacting via hydrophobic interactions. Thanks for any help you can provide. Phil McClean

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Copy attribute value from one attribute to another
by Sean Connell 02 Nov '22

02 Nov '22

Hello, I have a question with a probably obvious answer but I cannot figure it out. Is there a command to copy an attribute value from one attribute to another, for example, seq_conservation to bfactor? The idea would be to save a pdb file with the conservation stored in bfactor (for sharing). In this case I guess there is the issue that one is an atom attribute and the other is residue attribute but one could assign all atoms of the residue the same value. Sorry in advance if I miss something obvious.

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Get atom from selection string in script
by Thibault TUBIANA 02 Nov '22

02 Nov '22

Hi! I would like to create a function to copy the torsion angle from a model to another one. The function would take in argument the model ID of the reference and target model (<int>) and the residue id (<int>). I looked a bit at the scripts available in [ https://rbvi.github.io/chimerax-recipes/ | https://rbvi.github.io/chimerax-recipes/ ] to have an idea of how to add function in ChimeraX, but I'm currently stuck at "how to get the list of atoms from a selection string ?". Here's my current script from chimerax.core.commands import run def copy_torsion(session, model1, model2, residue): selection = f"torsion #{model2}:{residue}@n,ca,c:{residue+1}@n" from chimerax.atomic import AtomsArg atoms = AtomsArg(selection) from chimerax.geometry import dihedral cur_torsion = dihedral([*a.scene_coord for a in atoms]) torsion=run(session, f"torsion #{model1}:{residue}@n,ca,c:{residue+1}@n {cur_torsion}") def register_command(logger): from chimerax.core.commands import CmdDesc, register, FloatArg, IntArg, BoolArg, Color8Arg, StringArg from chimerax.atomic import AtomsArg desc = CmdDesc(required = [ ('model1', IntArg), ('model2', IntArg), ('residue', IntArg), ], synopsis='Copy torsion angle') register('copyTorsion', desc, copy_torsion, logger=logger) register_command(session) Thank you for your help :) Best regards, Thibault. -- Thibault Tubiana, PhD Postdoctoral Fellow @ [ https://www.i2bc.paris-saclay.fr/equipe-interactions-and-assembly-mechanism… | IMAPP ] Institute for integrative biology of the cell ( [ https://www.i2bc.paris-saclay.fr/ | I2BC ] ) - CNRS UMR 9198 CEA Saclay, 91191 Gif sur Yvette - Bât 532 pce 34 Web Site: [ http://www.tubiana.me/ | http://www.tubiana.me/ ]

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Re: [chimerax-users] [Chimera-users] xyz axis indicator
by Elaine Meng 01 Nov '22

01 Nov '22

Hi Xiang, I am guessing you are using ISOLDE with ChimeraX (not Chimera) so I am cross-posting this question to the chimerax-users(a)cgl.ucsf.edu list. I am not expert with ISOLDE so I am not sure about the answer. Best, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Department of Pharmaceutical Chemistry University of California, San Francisco > On Oct 30, 2022, at 10:58 PM, Xiang Zhang via Chimera-users <chimera-users(a)cgl.ucsf.edu> wrote: > > Hi all, > > I was wondering how I could hide the xyz indicator in the center of window when I was viewing the X-ray density from mtz file? It only appears in crystal unit view mode but disappears in EM projection side view. > > Best, > Xiang > <1667192316818.png>_______________________________________________ > Chimera-users mailing list: Chimera-users(a)cgl.ucsf.edu > Manage subscription: https://www.rbvi.ucsf.edu/mailman/listinfo/chimera-users

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Co-centering maps and pub models
by mailman-bounces＠cgl.ucsf.edu 01 Nov '22

01 Nov '22

Dear ChimeraX users I have a density map and a pdb model opened in ChimeraX. How to move one of them to have a common axis (for both) , without disturbing the other. Stay safe & Regards Anindito Sen. Ph.D Microscopy and Imaging Center Texas A&M University 301 Old Main Dr College Station, TX 77843-2257 Office: ILSB Room 1133 <http://microscopy.tamu.edu/>Tel. 979-458-9881 fax: 979-847-8933 http://microscopy.tamu.edu <http://microscopy.tamu.edu/>

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