June 2026 - phenixbb - phenix-online.org

.cif file has 'UNK' auth_asym_id
by Kevin M Jude 07 Jun '26

07 Jun '26

I’ve finished refining a structure with three protein chains A, B, C. The pdb file looks ‘normal’ to me, but when I inspect the .cif file written by phenix, the auth_asym_id for chains B and C is ‘UNK’. label_asym_id is correct for all chains. I’m not really sure what the difference is between the auth_ and label_ fields. When I try to perform actions on the .cif file, I get duplicate atom label errors. Here’s a few example lines from the .pdb and .cif files, where auth_asym_id is field 6 and label_asym_id is field 16 ATOM 460 OXT PRO A 59 5.272 55.689 31.481 1.00 52.63 O ANISOU 460 OXT PRO A 59 6541 6212 7244 1448 1260 96 O TER ATOM 461 N ALA B 2 39.292 61.974 39.403 1.00 67.81 N ANISOU 461 N ALA B 2 7118 8729 9916 -1711 -388 2066 N ATOM 460 OXT . PRO A 59 ? 5.27169 55.68852 31.48123 1.000 52.63052 O ? A ? 58 1 ATOM 461 N . ALA UNK 2 ? 39.29207 61.97430 39.40271 1.000 67.80544 N ? B ? 1 1 I’m able to convert the pdb file to a usable cif file using gemmi but wanted to report this weird behavior with phenix 1.21.2_5419. -- Kevin Jude, PhD Structural Biology Research Specialist, Garcia Lab Howard Hughes Medical Institute Stanford University School of Medicine Beckman B177, 279 Campus Drive, Stanford CA 94305

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Trouble with GTP/GDP refinement.
by DIEGO ORTIZ DE ELGUEA LOPEZ DE DICASTILLO 07 Jun '26

07 Jun '26

Dear phenixbb: I'm working with a GTP binding protein and have had some problems running phenix_refine. In my unit cell there are two molecules one with GDP and one with GTP, which I added in Coot(0.9.8). When refining the following error message pops-up : "Fatal problems interpreting model file: Number of atoms with unknown nonbonded energy type symbols:4 Please edit the model file to resolve the problems and/or supply a CIF file with matching restraint definitions, along with apply_cif_modifications and apply_cif_link parameter definitions if necessary". Checking the log file I found that the problem seems to be hydrogen atoms from these ligands Number of atoms with unknown nonbonded energy type symbols: 4 "HETATM 6499 H5' GTP A 501 .*. H " "HETATM 6502 H5'' GTP A 501 .*. H " "HETATM12939 H5' GDP B 501 .*. H " "HETATM12940 H5'' GDP B 501 .*. H " Including the corresponding .CIF files (dowloaded from PDB) did not solve the problem and the same error popped. Since I'm in the initial stages of the refinement I'm running phenix with bindividuals. Could anybody save my day giving me some light into this issue? Cheers, Diego

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CSD changes conformation to planar during phenix.refine
by Andrea Smith 07 Jun '26

07 Jun '26

Hi all, I have a structure where I clearly see that one of the cysteines is oxidised. I have modelled CSD instead of CYS and when I do real space refine in Coot, the CSD sits nicely in the density. When I submit the phenix.refine job, I can see that the geometry changes and now the SOOH is planar. I tried to add the CSD.cif from PDB into phenix.refine as restraints, but it doesn't help and during the automatic refinement the geometry is changed to planar again. Anyone experienced same thing? What do I do? Thank you, Andrea

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seeking help for phenix - coot model building
by tim smith 07 Jun '26

07 Jun '26

Hi everyone, I’m currently working on building a model and have encountered some difficulties with the map-model process. I would greatly appreciate it if anyone could assist me in either helping to build the model or teaching me how to do it. I’m happy to offer a suitable reward for your time and help. Thank you in advance for considering! Regards, Stim

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Issues with zero B-factor and ADP refinement
by sylee00＠snu.ac.kr 07 Jun '26

07 Jun '26

Dear all, I am encountering issues related to B-factors and ADP refinement in Phenix and would appreciate any insights or suggestions. I am currently working on my first PDB file, but I've noticed that many atoms in the PDB file have a B-factor of 0. As far as I understand, B-factor values are calculated by ADP refinement in Phenix real-space refinement, but even after running real-space refinement (with ADP on in refinement settings), the B-factor remains 0 for many atoms. I am currently using Phenix 1.20 on Windows (Newest version available on window). I also attempted to run Phenix 1.21 on a Linux in other computer, but when ADP refinement is enabled, the process starts normally but halts during the ADP refinement step. So I couldn't test whether the issue is fixed in the newest version. Aside from the B-factor issue, I am also experiencing an inssue related to ADP refinement: When I run real-space refinement with ADP refinement enabled, the process starts normally but halts during the ADP refinement step. According to the log file, other refinement steps proceed without issues, but it fails to progress at the ADP refinement stage. Additionally, when I try to pause the process, I receive a "NoSuchProcess" error, so ADP refinement process may have unexpectedly terminated. At first, I thought it's the issue related to system performance or hardware differences, because adp refinement with this pdb file and identical parameters works on some computer but fails on others (the same version of Phenix). Still it's weird because this issue has occurred unexpectedly, as ADP refinement previously worked in my computer under the same conditions without any problems and also other PDB files run without any problems in my computer. I would appreciate any insights or suggestions on how to resolve this. Thanks

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CloudFlare and Spain
by Billy Poon 07 Jun '26

07 Jun '26

Hi everyone, Does anyone in Spain have issues reaching the Phenix website ( https://phenix-online.org)? Our website is behind CloudFlare and it looks like, periodically, some CloudFlare IP addresses are blocked in Spain due to some piracy issues. Thanks! -- Billy K. Poon Research Scientist, Molecular Biophysics and Integrated Bioimaging Lawrence Berkeley National Laboratory 1 Cyclotron Road, M/S 33R0345 Berkeley, CA 94720 Fax: (510) 486-5909 Web: https://phenix-online.org

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for autobuild full sequence?
by James Holton 07 Jun '26

07 Jun '26

Hey all, Don't worry, nothing is funny today. I have a real question: Is there a way to force phenix.autobuild to build in the entire sequence? As in: the full length of the actual molecule that is in the crystal, such as what is supposed to go into SEQRES, regardless of "visible" density? I am trying to come up with a pipeline for prepping MD simulations of protein crystals. It seems proper to me that the molecule being simulated should be the actual molecular species, disordered bits an all. However, we don't seem to have good technology for building protein chains into "nothingness". Yes, I know Alphafold is a thing, but it is rubbish at clashes in the context of a crystal. I mean, I could write something, but does this tool already exist? Cheers, and happy Tuesday, -James Holton MAD Scientist

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Simulate map from model
by Ricardo Righetto 07 Jun '26

07 Jun '26

Hi, Apologies if I'm missing something obvious, but I was not able to find this in the documentation: is there a PHENIX tool for simulating Coulomb potential maps (aka "cryo-EM maps") from atomic models? I'm looking for something like the molmap <https://www.cgl.ucsf.edu/chimerax/docs/user/commands/molmap.html> command in ChimeraX, but more accurate. One such alternative is the simulate program from cisTEM, but I figured PHENIX might also have something? Thank you! -- Ricardo Diogo Righetto

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Question about geometry outliers in RealSpaceRefine
by Kevin M Jude 07 Jun '26

07 Jun '26

After a recent RealSpaceRefine run, the Geometry Restraints tab in the gui reports that I have two bond angle outliers > 4 sigma, but only lists one of them: D 180 MET N, D 180 MET CA, D 180 MET CB 114.170 109.342 4.2 So I check the logfile for the job and see: Bond angle restraints: 12582 Sorted by residual: angle pdb=" N MET D 180 " pdb=" CA MET D 180 " pdb=" CB MET D 180 " ideal model delta sigma weight residual 114.17 109.34 4.83 1.14e+00 7.69e-01 1.79e+01 angle pdb=" CA LEU B 79 " pdb=" CB LEU B 79 " pdb=" CG LEU B 79 " ideal model delta sigma weight residual 116.30 127.81 -11.51 3.50e+00 8.16e-02 1.08e+01 angle pdb=" C ASP B 333 " pdb=" N SER B 334 " pdb=" CA SER B 334 " ideal model delta sigma weight residual 122.74 127.19 -4.45 1.44e+00 4.82e-01 9.54e+00 angle pdb=" C GLN D 167 " pdb=" N ARG D 168 " pdb=" CA ARG D 168 " ideal model delta sigma weight residual 121.48 126.80 -5.32 2.04e+00 2.40e-01 6.80e+00 angle pdb=" C ASP B 163 " pdb=" N THR B 164 " pdb=" CA THR B 164 " ideal model delta sigma weight residual 123.47 127.30 -3.83 1.53e+00 4.27e-01 6.27e+00 ValidationCryoEM returns identical results except the gui says only one > 4-sigma outlier (at //D/Met180/). PDB Validation reports only the outlier at //B/Leu79/, which does have the largest sigma in the above log. My questions are: 1. Why does the gui report two 4-sigma outliers but only show one? 2. Why do the sigmas in the log file not correspond to the sigmas in the gui? Best wishes Kevin -- Kevin Jude, PhD Structural Biology Research Specialist, Garcia Lab Howard Hughes Medical Institute Stanford University School of Medicine Beckman B177, 279 Campus Drive, Stanford CA 94305

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DEN restraints and ECHT disorder models
by Roberto Battistutta 07 Jun '26

07 Jun '26

Dear all, From which version of Phenix are the DEN restraints and ECHT disorder models implemented in the ensemble refinement (as described in Ploscariu, N., Burnley, T., Gros, P. & Pearce, N. M. (2021). Improving sampling of crystallographic disorder in ensemble refinement. Acta Cryst. D77, 1357-1364)? Thank you very much, Roberto. Roberto Battistutta Associate Professor Department of Chemical Sciences University of Padua via Marzolo 1, 35131 Padova - ITALY tel. +39.049.827.5262 fax. +39.049.827.5829 roberto.battistutta(a)unipd.it

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