- ChimeraX-users - RBVI Mailing Lists

Q-Score not shown in output file
by Thu Nguyen 05 Jun '25

05 Jun '25

Hi, I am trying to calculate the Q-score of this density map and structure pair using the Q-Score plugin <https://cxtoolshed.rbvi.ucsf.edu/apps/chimeraxqscore> in ChimeraX and save the score to the output file. I loaded the 2 files to ChimeraX and used this command "qscore #2 toVolume #1 useGui false pointsPerShell 8 shellRadiusStep 0.100 maxShellRadius 2.00 referenceGaussianSigma 0.60 logDetails false outputFile /Desktop/q_score.txt" However, the output file is empty and I got the error message in ChimeraX. When I removed the outputFile option, it worked as normal and gave me the average score of .32. Do you know why it happened like this and what I should do to fix it? Thank you very much. Best regards, Thu

2 1

Select all truncated amino acids in model (though ISOLDE?)
by Vorländer,Matthias Kopano 05 Jun '25

05 Jun '25

Hi everyone, Is it possible to create a selector or python script to identify/match all truncated amino acids in a model? If not possible directly in ChimeraX, could ISOLDE offer a solution through matching to residue template “TRUNC_CB”? Thanks in advance, Matthias

3 3

Using measure area command
by jillian.baker＠som.umaryland.edu 04 Jun '25

04 Jun '25

Dear ChimeraX community, I am trying to use the 'measure area' command to measure the area using three atoms (essentially trying to calculate the area of a triangle). I have come up with the script of "measure area #2/b:44@o,97@ca,57@hz3" with 2 being model ID, b being the chain, and then the numbers being residues and the atoms are followed by the "@" symbol. I don't quite get an error here, but I get back "No surfaces specified." I can't seem to figure out away to specify a surface or use a different command to calculate the between these three points. Any help with this would be greatly appreciated. Thanks, Jill

2 1

Align molecule to axes
by Alexander Lee 03 Jun '25

03 Jun '25

Dear ChimeraX community, I have an optimized benzene ring that's floating in space. Is there a way to align that ring to one of the axes' planes so that 2 of the 3 cartesian coordinates read 0,0? Ex: C1 0.00 0.00 z1 C2 0.00 0.00 z2 C3 0.00 0.00 z3 etc Regards, Alex

2 1

Shading from N-terminus to C-terminus?
by Nick Matzke 02 Jun '25

02 Jun '25

Dear ChimeraX list, Thanks so much for this amazing software! I have a kind of obscure question for which I could not find an answer on Google. I've got the FliPQR-FlhB structure, from here: https://www.rcsb.org/structure/6S3L This has 5 copies FliP 1 copy FliR 4 copies FliQ 1 copy FlhB I opened it and am using ribbon view. I've colored the chains by protein type with these commands: color /a,b,c,d,e purple color /f red color /g,h,i,j green color /k yellow Now, I'd like to have each chain shaded from N-terminus to C-terminus, e.g. dark red to light red, or something like that. (I see the rainbow option, but this creates a very complex view if all 11 chains are each an roygbiv rainbow.) Almost as good, is there a way to easily label the N-terminus and C-terminus of each chain? Any suggestions! Thanks so much, Cheers, Nick

2 2

ChimeraX support: Alphafold contacts
by Anthony Newcombe 02 Jun '25

02 Jun '25

Hello I have a commercial license of ChimeraX, I have a question you may be able to help with I have used Structure prediction > Alphafold to predict structures and interactions between 2 proteins and this returned the best_model.pdb But I would like to identify contacts within 8 angstroms, as shown in the Youtube video: https://www.youtube.com/watch?v=TMcjEecFHaI&list=WL&index=26'm typing the command: alphafold contacts /A to /B distance 8 But receive the error: 'Structure best_model.pdb #1 does not have PAE data opened' Do I need to open something? If you can help that would be much appreciated Many thanks Tony Anthony Newcombe PhD Applied Biopharm Consulting Ltd Cork, Ireland http://www.appliedbiopharm.com<http://www.appliedbiopharm.com/> IE: +353 (0)87 3634486 [cid:image001.png@01DBD2E1.AD97E890] Applied Biopharm Consulting Limited is a company located in the Republic of Ireland Reg. No: 747251, VAT No: IE4188817RH. Registered office: Brook Lodge, Lisnacunna, Ballinascarthy, Clonakilty, Cork, Ireland P85 C832. This message is confidential and intended solely for the recipient(s). If you are not the intended recipient, any use, disclosure, copying or distribution of this message or its attachments is strictly prohibited. Please notify the sender immediately by replying to this email and delete the message, its attachments and any copies.

3 2

Comparing Maps
by Abhilash Padavannil 02 Jun '25

02 Jun '25

Hello, I have five different cryoEM maps coming from similar samples. The maps are at different resolutions. I want to compare the density at the region of interest across these maps. How do I normalize the maps say to the first map to make accurate analysis. I know I could scale them using vop scale, but I am wondering which of the parameters I should use. Thanks in advance for your suggestions. Abhilash.

3 4

How to create singlke protein from assembly of 5 individual chains
by Jacek Jagodzinski 29 May '25

29 May '25

Hi, I am medicinal chemist. I used ChimeraX to model missing parts/loops of the protein for which I had cryo-EM structure. It is transmembrane protein consisting of 5 individual chains. I managed to reconstruct missing parts using as a template known sequences of publicly available X-ray structures of proteins and known sequences. I have now a nice assembly of five individual “repaired” proteins perfectly aligned with parts of my cryo-EM structure. However the PDB file of those FIVE individual proteins is not recognized as ONE protein with five separate chains by my other programs. I suppose there is a way to get the result I need, but I cannot find the solution by myself. Can you help? Jacek Jagodzinski, PhD

2 4

Use minimization in chimerax using command line
by TUSHAR GUPTA 29 May '25

29 May '25

Good morning I would like to appreciate your work and efforts in developing and maintaining ChimeraX, it has always been so useful tool in my research. I was initially using Chimera that had excellent feature of using amber force field for energy minimization of structure and making movie using topology and coordinate file. I am working on inducing mutation in nucleic acid and protein structures. I wish to incorporate the minimization step in my research using Chimerax. I will be highly grateful if you could guide me how can I use minimization steps in Chimerax using command line codes. Thank you Tushar Gupta PhD biotechnology Bennett University Greater Noida India "He that can have patience can have what he will." - Benjamin Franklin _____________________________________________ Vineet Jain (Chancellor) Inspiration

2 4

Issue in using vop maximum to make composite map
by Dr. Heng Zhou 29 May '25

29 May '25

Dear ChimeraX developers, I have an issue when using vop maximum command to combine two local maps. Map A and Map B have an overlapping area with each other. The hinge point of structural flexibility is at the center of the overlapping area. Therefore, the left part of Map A and the right part of Map B have a better local density quality, which I want to keep in the composite map. But vop maximum did it on the opposite, resulting in a worse local resolution at the edges of the overlapping area (e.g., Region 1 and 2). Technically, this is not an issue of vop maximium itself. In Region 1, Map A has a better local density quality, while Map B has higher values in some voxels. So the composite map has more voxels derived from Map B in Region 1. Vice versa for Region 2. The only solution in my mind is to split both Map A and B at the hinge point, then do vop maximum for only the left part of Map A and the right part of Map B. But this is time-consuming since I have many local maps to combine. I wonder if you have a better solution? I would appreciate it if you could give advices. Thanks! Best regards, Heng Heng Zhou, PhD | Postdoctoral research fellow Stefan Raunser lab | Structural Biochemistry Max Planck Institute of Molecular Physiology Otto-Hahn-Straße 11, 44227 Dortmund, Germany Phone: +49 231-133-2326

5 7