September 2025 - ChimeraX-users - RBVI Mailing Lists

Just a Big Thank You
by Esmaeeli,Reza 25 Sep '25

25 Sep '25

Dear ChimeraX Developers, This is Reza and I’m a computational chemist and protein designer. I’ve been a long time user of Chimera and now ChimeraX. Among many visualization programs that I have tried extensively including PyMOL, VMD, Maestro, ChimeraX has remained my favorite. I just wanted to take a moment and write this email just to say thank you for your amazing work. Even though it is free for academic users, this email is the least I should do after so many hours that I have enjoyed using it. The interface is great. The diverse set of features and modules are awesome. And the command line and scripting capabilities are so intuitive and easy to use. Can’t wait to see what comes next. Best Regards, Reza ChimeraX 1.10.1 on macOS Tahoe

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Chimera and ChimerX issues after update to MacOS Tahoe
by Rechiche, Othman 24 Sep '25

24 Sep '25

Hi everyone, I recently updated to MacOS Tahoe, Since then I encountered several issues with Chimera, ChmieraX and python. I installed and removed and reinstalled the apps but I still get the same error. For chimera I get this error: [Screenshot 2025-09-24 at 12.08.51 AM.png] FOr ChimeraX, when I try to open a session, it complains that the session was created with another version of python. I opened that session successfully several times before to the update of MacOS and I have never seen this error before. Failed opening file /Users/x/x/x/x/x/x/x/x.pyc: Python code was compiled for a different version of Python Can you please help me fix this? Best Regards, Othman Dr. Othman Rechiche Herbert Irving Comprehensive Cancer Center Columbia University Medical Center Columbia University New York, NY 10032 email: or2296(a)cumc.columbia.edu phone: +1 (814) 880-5554

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Suggestion for viewdock
by John Irwin 24 Sep '25

24 Sep '25

Hi Team We love viewdock. We would like to suggest allowing hotkeys for adjusting status e.g. for prioritization so that we do not need to mouse all the way down to click to change status. We think this might be a small change with a big usability and productivity impact. Thank you John John Irwin UCSF Pharmaceutical Chemistry http://irwinlab.compbio.ucsf.edu

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Is there a way to download a pdb and it's associated density map in one command
by Samuel Haysom 24 Sep '25

24 Sep '25

Is there any way I can fetch a pdb file from the web (e.g. $ open 1X2Y) and then also automatically fetch the associated cryoEM map if there is one? Looking in the mmCif file, there is a flag for the associated emdb-map (e.g. in 5ljo the mmCIF file there is a _pdbx_database_related.db_id flag with the corresponding id. It would be useful if this could be added as a flag to the open command if it isn't already. I'm sure it is also possible in some kind of script but I'm not hugely familiar with how to script in chimeraX. Samuel Haysom Senior Scientist • Protein Sciences Nxera Pharma UK Limited +44 (0)1223 949201 • Steinmetz Building, Granta Park, Great Abington Cambridge, CB21 6DG, United Kingdom The information in this e-mail is confidential and may be legally privileged. It is intended for the exclusive attention of the addressee stated above and should not be copied or disclosed to any other. If you have received this transmission in error, please contact the sender immediately, make no use of its contents and delete this message from your system. Contact and registered office address: Nxera Pharma UK Limited, Granta Park, Great Abington, Cambridge, CB21 6DG. Company No: 06267989.

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Ligand center
by NUR AIDA SAKINAH 24 Sep '25

24 Sep '25

Hi ChimeraX teams, I want to search ligand center for docking analysis. What command do I need to use to retrieve the ligand center (x,y,z)? Example pdbid is 4yvv and the ligand is GBM. So i want the GBM's x,y,z coordinates. Thank you. Regards, Aida.

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Regarding the method used by chimeraX for SASA calculation
by Prathvi Singh 23 Sep '25

23 Sep '25

Hi Elaine, I have used NACCESS ( https://www.bioinf.manchester.ac.uk/naccess/nac_intro.html) to calculate the SASA for a protein. It used the Lee & Richards (1971, J. Mol. Biol., 55, 379-400) method to calculate SASA. I wanted to know whether chimeraX also uses the same method to calculate SASA or not. If not, then can you mention how the chimeraX method differs from the method used by NACCESS? Thanks in advance, Prathvi Singh, Research Fellow, Department of Biological Sciences & Bioengineering, Indian Institute of Technology, Kanpur-208016

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About "Minimizing Structure" feature in Chimera
by Zheyun Wang (MED,124090655) 23 Sep '25

23 Sep '25

Dear ChimeraX developers: I am Wang Zheyun, a student in Chinese University of Hong Kong, Shenzhen. In my computational biology course, our professor demonstrated to us that the molecular structure (a file containing several water molecules) can be changed to an energy-minimizing structure using "Minimizing structure" function in Chimera. However, I cannot find this function in ChimeraX(1.10.1), and professor told me that these two are completely different softwares. Is this function available in ChimeraX? If so, may I know where it is? If not, will this be added to ChimeraX or is it deliberately deleted? Looking forward to your reply! Sincerely, Wang Zheyun

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Python API: locate_maximum logic
by nrajan53045＠utexas.edu 19 Sep '25

19 Sep '25

Hi there, I was hoping to implement something similar to the rigid rotation/translation optimization within fitmap due to its efficiency. I have some code which appears to implement the same logic as locate_maximum from your github, but is returning wildly different affine matrices than I expect. I just had a couple of questions regarding the logic: 1) locate_maximum receives an conversion matrix from world to voxel space (xyz to ijk) as one of its parameters from volume's matrix_and_transform function. I was wondering what this matrix actually is? I was tracing through the matrix_and_transform function and I couldn't really figure this out. I am currently assuming that the transform matrix is a 3 x 4 affine matrix: 1/v * (I | -O). Where v is the isotropic voxel size, I is a 3 x 3 identity matrix and O is a 3 x 1 vector representing the origin of the map. 2) Within each step of a segment, the following is done (from steps_to_maximum): ``` if step_types: for step in range(steps): calculate_step = step_types[step % len(step_types)] xyz_to_ijk_tf = xyz_to_ijk_transform * move_tf step_tf = calculate_step(points, point_weights, rotation_center, data_array, xyz_to_ijk_tf, ijk_step_size, metric, syminv = syminv, values = values, gradients = gradients) move_tf = move_tf * step_tf ``` In this loop, xyz_to_ijk_transform looks like the full conversion matrix from world to voxel space. But each iteration also multiplies it by move_tf before applying the step calculation, and then updates move_tf again with step_tf. At first glance, it seems like we’re reapplying the same full transform at every step... so why not just apply it once, instead of multiplying it repeatedly inside the loop? And then when we return to locate_maximum, move_tf is once again applied to the full conversion matrix. before continuing the iteration. I apologize if this is nitty gritty detail, but I would really like to make sure my logic is sound when I am implementing my version of this algorithm. Thank you for your time, Nikhil Rajan

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Generate a volume from a shape
by Guillaume Gaullier 18 Sep '25

18 Sep '25

Hello, I am trying to do something seemingly simple, but can't figure out what I am doing wrong. I have an mrc map open as model #1, moved the center of rotation somewhere, then generated a sphere with: shape sphere radius 30 center cofr I got a sphere as model #2, good. Then I want to turn this sphere into a mask, which I try doing like this: volume onemask #2 ongrid #1 At which point I get this error: Expected a density maps specifier or a keyword The documentation of 'volume onemask' says it needs a surface specification as the first argument, and the model panel shows that there is no surface associated to the sphere (then why/how is it displayed? not sure), so that all seems to make sense. And I am stuck at this step: how do I turn this sphere into a surface so I can generate a volume from it? I read the documentation for 'surface', 'volume' and 'shape' but can't find anything to solve this problem. Thank you in advance, Guillaume 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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Predicting and modeling post-translationally modified C-terminal endings
by Parks, Ryssa 16 Sep '25

16 Sep '25

Hello, I am trying to predict and model a peptide docking to a receptor protein using ChimeraX's AlphaFold interface, and I was wondering if there is any way to specify post-translational modifications in the AlphaFold input function in ChimeraX? Our peptide has an amidated C-terminus, and my searches online have not yielded much success. Thank you, Ryssa Parks

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