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Inquiry About Favorable Contacts and Display Methods in ChimeraX
by 田畑　健士郎 07 Mar '25

07 Mar '25

Subject: Inquiry About Favorable Contacts and Display Methods in ChimeraX Dear ChimeraX Developers, My name is Kenshiro Tabata. I hope this email finds you well. I am currently using ChimeraX to analyze the effects of point mutations on protein structure, particularly in cases where a larger side chain (e.g., methionine) is replaced by a smaller one (e.g., valine). In such cases, I expect that interactions with the opposing amino acids may be reduced due to the decreased side-chain volume. To investigate this, I would like to ask for your guidance regarding the interpretation and visualization of favorable contacts. ________________________________ 1) Understanding Favorable Contacts I understand that the contacts command identifies all types of interactions, whereas the clashes command detects only unfavorable interactions. Based on this, I interpreted the positive VDW overlap as indicating unfavorable (repulsive) interactions, while an overlap between 0 and -0.4 represents favorable (attractive) interactions. Could you confirm if this understanding is correct? ________________________________ 2) Best Approach for Displaying Only Favorable Contacts To analyze how the mutation affects interactions, I would like to display only favorable contacts. Below is the approach I have considered: Proposed Approach 1. Retrieve all interactions (favorable, neutral, and unfavorable) using the contacts command contacts overlapCutoff -0.4 saveFile all_contacts.txt 2. Retrieve only neutral and unfavorable interactions contacts overlapCutoff 0 saveFile non_favorable_contacts.txt 3. Compute the difference between these two sets using Python, extract only favorable contacts, and format them into a ChimeraX pseudobond file # File paths all_contacts_path = "all_contacts.txt" non_favorable_contacts_path = "non_favorable_contacts.txt" favorable_contacts_path = "favorable_contacts.pb" # Read files with open(all_contacts_path, "r") as f: all_contacts = set(f.readlines()) with open(non_favorable_contacts_path, "r") as f: non_favorable_contacts = set(f.readlines()) # Extract favorable contacts favorable_contacts = all_contacts - non_favorable_contacts # Convert to ChimeraX pseudobond file format with open(favorable_contacts_path, "w") as f: f.write("; Pseudobond file for favorable contacts\n") f.write("; radius = 0.1\n; color = green\n; dashes = 6\n") for line in favorable_contacts: parts = line.strip().split() if len(parts) >= 4: atom1 = f"/{parts[0]}:{parts[1]}@{parts[2]}" atom2 = f"/{parts[3]}:{parts[4]}@{parts[5]}" f.write(f"{atom1} {atom2}\n") 4. Load the extracted favorable contacts into ChimeraX for visualization open favorable_contacts.pb Would this be an appropriate approach? Alternatively, is there a simpler or more precise way to achieve this in ChimeraX? I appreciate your time and assistance, and I look forward to your advice. Best regards, Kenshiro Tabata

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AI in ChimeraX
by Elaine Meng 07 Mar '25

07 Mar '25

On Mar 7, 2025, at 6:01 AM, Veach, Kevin G. <kevin.veach(a)uky.edu> wrote: > > Hi Elaine: > Does Chimera-X use Artificial Intelligence or Large Language Learning Models? > Thank you, > > Kevin > Kevin Veach, Computer Support Specialist II > University of Kentucky, Animal & Food Sciences Dept. Hi Kevin, Please use the chimerax-users(a)cgl.ucsf.edu <mailto:chimerax-users@cgl.ucsf.edu> address CC'd here for general questions about ChimeraX -- I'm not the top expert on all parts of ChimeraX, so you may get better answers from other developers or our user community. Regarding your question, my understanding is that ChimeraX itself does not use these kinds of calculations, but it has tools that interface to web services or other calculations (run outside of ChimeraX) that do use them. The ones that I can think of are AlphaFold/ColabFold and ESMFold: <https://rbvi.ucsf.edu/chimerax/docs/user/tools/alphafold.html> <https://rbvi.ucsf.edu/chimerax/docs/user/tools/alphafold.html#predict> <https://rbvi.ucsf.edu/chimerax/docs/user/tools/esmfold.html> <https://rbvi.ucsf.edu/chimerax/docs/user/tools/esmfold.html#predict> 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

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Creating movie in ChimeraX from YASARA simulation
by ibogdanov 07 Mar '25

07 Mar '25

Hi ! I have the following question - How can I create a movie, when I cannot use the YASARA.sce file from which I converted/extracted xtc.file(the trajectories) when I have all the snapshots(pdb and sim.files) created as separate files during the performed simulation in YASARA...I've uploaded for example the first pdb file of the series and the xtc.file but isn't the saved xtc.file(trajectories) of the whole simulation(for all the structures)? How would you suggest me to solve this problem, if ChimeraX doesn't support sce.files ? Thank you in advance! Kind Regards, Ivan Bogdanov

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Problem installing on OSX
by Thom Hughes 06 Mar '25

06 Mar '25

I apologize for the dumb question, but here it is. I want to install the isolde extension. When I go to more tools, isolde, and click the install button a .whl file downloads correctly. But then nothing happens. I’m running OSX 15.3.1. thanks in advance for any pointers!

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Unable to open the file after downloading ChimeraX
by Guo-Ping Zhou 05 Mar '25

05 Mar '25

Dear Sir/Madam, After downloading ChimeraX, I automatically get the attached .png in the application as a microsoft word file. However, I can't open the Quick Access Toolbar. Could you please tell me how to make it work? Thanks! Guo-Ping Zhou, Rocky Mount Life Sciences Institute, Rocky Mount, NC 27804

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(no subject)
by FRANGIE Christian 05 Mar '25

05 Mar '25

Dear UCSF ChimeraX Support Team, My name is Christian frangieh, I am currently using Chimera X to visualize my AlphaFold simulations, and I want to check when i introduce a mutation and change one residue (amino acid), whether there is a change in the surface accessibility of the residue. Currenlty i am checking this visually by checking whether the residue is exposed to the surface or hidden. Nevertheless, i would like to know how can i do this with a command or by some form of calculation or structural analysis. Can you please help me with this matter? Warm Regards, Christian

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Can not find Structure Minimization in ChimeraX menu
by N.B. Nugroho 04 Mar '25

04 Mar '25

Dear ChimeraX developers I a little bit confuse to find the Structure Minimization menu in ChimeraX. In Chimera 1.16 it located in menu Tools>Structure Editing>Minimize Structure. Could you please guide me for this little problem. Best regards Nuki B Nugroho

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(no subject)
by junjie han 02 Mar '25

02 Mar '25

Hi, I hope you are doing well. May I ask two questions? First one: Why does the connection part between the side chain and backbone, which is circled in a dashed line in ChimeraX, look so abnormal? How can I make it display normally? [cid:437c0c59-2e31-4251-ac9c-eff3f64af0dd] Second one: Is it possible to show the border only for a specific region of protein without hiding other regions? Thanks, Junjie

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define integer attributes for multiple individual pseudobonds
by hannes.ludewig＠googlemail.com 28 Feb '25

28 Feb '25

Dear developers, I am trying to color pseudobonds by an individual (per-bond) attribute value (integer). I seem to be unable to use .pb files to create individual pseudobonds. And when I am using the pbond command several times providing an individual name for each pseudobond thus creating individual models (#1.1, #1.2, etc) I am unable to assign an attribute and color all pseudobonds according to the corresponding attribute value. What I want to create is similar to the alphafold contacts colored by PAE. Only that the values I am providing aren't PAE and I would like to determine the residue pairs that form each pseudobond. I apologize in case I am overlooking something obvious, but your help and/or clarification would be very much appreciated. Thank you. Best wishes, Hannes

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Disulphide bridges in ISOLDE
by Guillaume Gaullier 28 Feb '25

28 Feb '25

Hello ISOLDE users and Tristan, Is there a distance threshold at which ISOLDE won't let me close a disulphide bridge? I am puzzled, because it seems I can close a disulphide between two Cys about 10 residues apart in sequence and quite far from each other in space. In fact much further apart than a bond length, so the resulting bond looks ridiculously stretched. But it is quickly fixed when running a local simulation, even if it needs to pull the backbone out of density to achieve a reasonable S-S bond length. In the same model, I have two other Cys that follow each other in sequence. When loading the AlphaFold prediction, the two S atoms are close enough (for some reason) that ISOLDE offers to make the disulphide, so I say yes. Later on, wanting to test both options to assess which one is best supported by the map, I can break this disulphide, but once I do there is no way to close it again. In this case, the two S atoms settle about 3.4 Å apart when removing the bond, which is longer than an ideal disulphide, but much shorter than the distance over which ISOLDE still allowed me to form a disulphide in the first case. The documentation doesn't say anything about disulphides (or somehow I missed it). In fact, there seems to be no command to operate on disulphides? Using the menu item does not write anything to the Log, so if there is a command I cannot find what it is and what options it might accept. If someone can help with this, I would appreciate it! Thank you, Guillaume --- Guillaume Gaullier, PhD Researcher, Blikstad group Molecular Biomimetics / Microbial Chemistry Department of Chemistry - Ångström Uppsala University Lägerhyddsvägen 1 752 37 Uppsala Sweden När du har kontakt med oss på Uppsala universitet med e-post så innebär det att vi behandlar dina personuppgifter. För att läsa mer om hur vi gör det kan du läsa här: http://www.uu.se/om-uu/dataskydd-personuppgifter/ E-mailing Uppsala University means that we will process your personal data. For more information on how this is performed, please read here: http://www.uu.se/en/about-uu/data-protection-policy

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