July 2025 - ChimeraX-users - RBVI Mailing Lists

An error opening chimerax seesion
by Yehuda Halfon 11 Mar '26

11 Mar '26

Hi all, I'm using chimeraX 0.8 (2018-12-17) on centos 7 (can't remember the build). Sometimes when I load a session that was saved using this version of chimeraX it gives me this error: Unable to restore session, resetting. Traceback (most recent call last): File "/software/graphics/chimerax/lib/python3.6/site-packages/chimerax/core/ session.py", line 593, in restore obj = sm.restore_snapshot(self, data) File "/software/graphics/chimerax/lib/python3.6/site-packages/chimerax/ std_commands/view.py", line 214, in restore_snapshot for k,v in data ['view attrs'].items(): TypeError: 'NoneType' object is not subscriptable After that I can't open the session again, so I need to remake it. Help, Yehuda Halfon

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VR on ubuntu workstation
by arangarajan＠initialtx.com 04 Mar '26

04 Mar '26

Hi, i got steam VR installed but later found out that Oculus does not support linux. Is there a work around for using chimerax VR on latest ubuntu machine with oculus rift s headset? i can get other headset also if it will fit this purpose. thanks in advance, best amith

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ISOLDE and secondary structure restraints
by Guido Hansen 02 Mar '26

02 Mar '26

Hi all, I just started model building in cryoEM maps and get great results using ISOLDE on AlphaFold2-derived initial models. I have a question which is mainly directed to Tristan I guess: Is is possible to use the command line/script to apply secondary structure restraints in ISOLDE? I would like to restrain the initial secondary structure assignment from Alphafold especially at resolution worse than 3.5 A. At the moment I select each and every residue range assigned to helix, parallel or antiparallel beta-strand one after the other and turn on the corresponding restrains in the ISOLDE GUI. Is there a better way via command line of script? Cheers, Guido -- PD Dr. Guido Hansen Group Leader UNIVERSITÄT ZU LÜBECK INSTITUT FÜR BIOCHEMIE Tel +49 451 3101 3122 Fax +49 451 3101 3104 E-Mail hansen(a)biochem.uni-luebeck.de www.biochem.uni-luebeck.de [1] Ratzeburger Allee 160 23562 Lübeck Links: ------ [1] http://www.biochem.uni-luebeck.de

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Volume eraser as cube?
by Oliver Clarke 25 Feb '26

25 Feb '26

Hi all, Hope the chimeraX team & community are having a great start to 2025! There are often situations (in single particle cryo-EM) where I would like to erase using a plane rather than a sphere - e.g., when I want to chop off density protruding from a nanodisc or micelle in order to make a mask. There are various workaround ways to do this (e.g. just making the sphere enormous, making a cubic/rectangular mask and multiplying/substracting, etc), but I was wondering if this is a common enough scenario (perhaps other users can chime in?) that it might be worth adding the option of erasing using a cube rather than a sphere? Cheers Oli

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ChimeraX version 1.9 has been released
by Elaine Meng 23 Jan '26

23 Jan '26

UCSF ChimeraX version 1.9 has been released! ChimeraX includes user documentation and is free for noncommercial use. Download for Windows, Linux, and MacOS from: https://www.rbvi.ucsf.edu/chimerax/download.html Updates since version 1.8 (June 2024) include: - Foldseek search and analysis of large sets of similar structures - Find Cavities tool and "kvfinder" command to identify pockets and channels in macromolecules - optional residue-level summaries of H-bond and contact calculations - "mutationscores" command for analysis and plotting of results from deep mutational scanning - "surface hidefarblobs" command for colocalization analysis of light microscopy channels - raycasting option for medical images or other maps displayed as transparent volumes - selection can be expanded to all residues associated with the same column(s) in a sequence alignment - protein structure metadata can be updated with full chain sequences - missing-structure pseudobonds are labeled with the number of missing residues (default, can be turned off in preferences) For details, please see the ChimeraX change log: https://www.rbvi.ucsf.edu/trac/ChimeraX/wiki/ChangeLog On behalf of the team, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Resource for Biocomputing, Visualization, and Informatics Department of Pharmaceutical Chemistry University of California, San Francisco

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Focus in ChimeraX
by Luca Pellegrini 10 Oct '25

10 Oct '25

Hi, What is the ChimeraX equivalent to the Focus command in Chimera? I have selected a portion of a structure, and would like to bring it into focus without dragging it into view. Also Focus would automatically set the selection as the pivot point. Best wishes, Luca Luca Pellegrini, PhD Department of Biochemistry University of Cambridge Cambridge CB2 1GA lp212(a)cam.ac.uk

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saving submodels as separate pdbs
by Alexandra Zahradnikova 30 Jul '25

30 Jul '25

Hi All, I have a trajectory (xtc) from which I can read selected frames into ChimeraX. I can then write all frames as one pdb with many submodels. But I am not able to find out how to open the frames as separate models, or save the trajectory as separate models. I will appreciate your help. Best Sasha Zahradnikova

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ViewDock Feedback and Feature Requests
by Andrii Kyrylchuk 29 Jul '25

29 Jul '25

Hi ChimeraX team! I would like to thank you for all the magnificent work you’re doing! My work would be much harder if Chimera and ChimeraX wouldn’t exist! After testing the new ViewDock (not ViewDockX), I have a few suggestions: 1. The rating system is still a bit inconvenient to use. A quick “OK/Bad” checkmark and fixed buttons to score the current ligand (as in classic Chimera) would speed up triaging. Dragging to each cell now slows review. 2. It would be great to have a possibility to rearrange columns. Now their order seems fixed. 3. It’s impossible to select and copy text in the lower part of the window. It would be very helpful in case I want to look into a specific ligand, e.g. copy its SMILES and visualize the 2D structure. 4. The window width follows the longest data field, leaving wide blank areas (see the screenshot). Could you allow arbitrary window sizes? Thanks for considering these ideas, and for all your ongoing work on ChimeraX. Sincerely, Andrii 

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How to replace ss_id for a secondary structure region?
by Rayees Mattoo 25 Jul '25

25 Jul '25

Hi, I have a region in my structure (res 208-229) which is displayed as a discontinuous helix when I am certain it is a continuous helix. I want to modify the pdb file to consider it as a continuous helix using chimeraX. I used the following commanlines: settatr #1/K:208-229 res ss_type 1 setattr #1/K:208-229 res ss_id 999 It works. However, I believe the command assigns the same region with a new unique ss_id (999), leaving the original ss_id intact. If I want to replace the the original ss_id with a new sequence range (res 208-229) how would I do that? Also, is there a way to directly text edit pdb file secondary structure list in ChimeraX? Best Rayees

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ChimeraX color fromcartoon error
by Prafful Sharma 25 Jul '25

25 Jul '25

* Dear ChimeraX Developer, I was recently trying to color a model in chimeraX based on a similar model with the same chain IDs and residues, and so I was using the command color fromcartoon #1 target #2 as specified in the documentation however I am receiving an error that says " Expected a color or one of 'byatom', 'bychain', 'byelement', 'byhetero', 'byidentity', 'bymodel', 'bynucleotide', 'bypolymer', 'fromatoms', 'fromcartoons', 'fromribbons', or 'random' or a keyword". I assume it is asking me to add a specific color name/code, but the other models have many different colors. I tried multiple turnarounds and even took help from different AI models, but still could not solve the error. I therefore think the functionality is not active, or there is some issue with I am not able to figure out. Can you please let me know if this functionality is working, or if there is any other way I can do this? Thank you for ChimeraX and your kind help! Prafful Sharma Ph.D candidate, TH lab | Structure, function, and regulation of protein synthesis Dept. of Developmental Biology and Genetics, Indian Institute of Science, Bangalore 560012

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