October 2025 - ChimeraX-users - RBVI Mailing Lists

Save centroids in scene coordinates
by Andrew Kennard 03 Oct '25

03 Oct '25

Hi there, I have aligned a bunch of models with matchmaker, and then I defined centroids for each model with `define centroid`. I would like to export those centroids for further analysis (trying to see the spatial relationship between chains B from each model when all models are aligned on chain A). However, the only way I could figure out how to do it was to press "Save Info..." in the Structure Measurements window. This text file reports the centroids in the model coordinate system for each model. But because I aligned the models with matchmaker, I'd rather have the centroids in the scene coordinate system. I am not sure how to do this transformation and export all the coordinates (~dozens of models). The only other option I found that might work was the `getcrg` command which I could use to save the coordinates to the Log, but then I will have to save the log as an HTML and parse that, right? Is there any more straightforward way? Alternatively, is there a better way to define centroids (ideally programmatically) so I can extract them from Chimera easily in scene coordinates? Perhaps the measure center command is the thing I should be using? Thanks a bunch! I'm running ChimeraX v1.10.1 (2025-07-24) on Mac OS 15.6 Sequoia Thank you!! Andrew

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de novo octahedral assembly of AlphaFold-generated ferritin monomers
by jmcquaid＠ucsd.edu 03 Oct '25

03 Oct '25

Hi folks! I would like to use "Sym # O" to model how a novel marine ferritin might assemble into an octahedral nanocage. Like ferritin, this marine ferritin is thermostable and has a size consistent with a 24-mer, but the AA sequence is too divergent to use 'matchmaker'. I've noticed that if I create a fold model of human ferritin (1FHA) with AlphaFold and import it into ChimeraX, the 'sym # O' command generates a 24-mer hairball rather than an octahedrally-coordinated sphere. If I 'fetch' the same 1FHA protein directly from PDB, the spherical structure is correctly assembled. What additional commands might be needed to help ChimeraX correctly assemble an AlphaFold-generated 1FHA monomer into the canonical ferritin cage? Chimera used to have a 'group 432' command, but I see this is not currently supported. Thanks in advance! Knowing how to correctly assemble something known like human ferritin will greatly help in assembling something unknown like a marine ferritin. Best Regards, Jeff McQuaid, Scripps Institution of Oceanography

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Re: [Chimera] local resolution map colors
by Elaine Meng 03 Oct '25

03 Oct '25

Hi, This question was sent to the commercial licensing address -- for user questions, please use the email address chimerax-users(a)cgl.ucsf.edu <mailto:chimerax-users@cgl.ucsf.edu> CC'd here to ensure that you get an answer instead of mystified silence. Is the local resolution map open in addition to the original map? I only see two copies of the same map in the Volume Viewer. Make sure that you open the local resolution map instead of a second copy of the original map. I hope this helps, 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 > On Oct 3, 2025, at 2:07 PM, Roy Chowdhury, Shatabdi wrote: > Hi, > > In the past, I've used chimerax to display local resolution on maps using the tools->volume data->surface color function. In a new map, I'm having difficulty with it. I'm attaching screenshots where the phenix local resolution job suggests the resolution range to be 1.27A - 4.6A range which is in agreement with cryosparc. When I load the cctbx_program.ccp4 file on chimerax, it is unable to color the surface and says the surface values are -0.067 - 0.107. Is there something I should be doing differently? Any suggestions would be deeply appreciated. > > Thanks! > > Shatabdi Roy-Chowdhury, PhD. > Cardiovascular Research Institute > University of California, San Francisco > > _______________________________________________ > Chimera mailing list -- chimera(a)cgl.ucsf.edu > To unsubscribe send an email to chimera-leave(a)cgl.ucsf.edu

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