- phenixbb - phenix-online.org

map deposition strategy after density modification
by Daniel Larsson 20 Sep '23

20 Sep '23

Hi Phenix community, I’ve been using density modification with some success for my data and am considering the most appropriate way to do model building/refinement and then deposition of my results. Here are some questions/observations: 1) Which map should I refine against (most importantly, do the final minimization using phenix.real_space_refine)? The DM map is the most clear one, so I’m favoring to do it against this one (as long as the geometry/validation is also best for this one). 2) Which map should I deposit as my main map? Is it the autosharpened one or the DM one? Since the DM map looks the best, I want the user who only downloads one map to see this one, so again I favoring this map. 3) Which nominal resolution should I quote for my reconstruction? Since the procedure seems to introduce correlation between the two maps (see point 4 below), it does not seem to be possible to obtain a gold-standard FSC value between two truly independent half-maps. As the DM procedure supposedly actually improves the map (by leveraging knowledge about what solvent and macromolecular maps usually looks like and thereby improves the Fourier coefficients), it feels like it would be misrepresenting the data by quoting the FSC_0.143 from the original reconstruction. Should I use the FSC_0.5 estimated value that phenix.resolve_cryo_em outputs? 4) Which FSC curve should I deposit? When I calculate the FSC between the two density modified half-maps, I get a funny (or rather not so funny) looking curve with a bump at around 3Å and it does not go to zero at Nyquist (which does not agree with the map quality). This must again be due to the induced correlation between the maps, presumably during the masking of solvent and macromolecule density. Phenix.resolve_cryo_em calculates a FSC curve to calculate the FSC_0.5 value, which according to the manual page corrects for the correlation induced between the two maps: "Density modification introduces some correlations between half-maps due to solvent flattening. This can have a small effect on the resolution estimates obtained with half-map FSC. The resolution estimates provided by the program are corrected for this effect." But is this curve good enough? I think OneDeposit wants to have the gold-standard FSC curve, right? 5) Which (nowadays mandatory) half-maps should one deposit? Here I would say that the original half-maps before DM makes more sense, since these are less processed. But if one specify these as the half-maps, there will be inconsistencies during validation, since the DM map will look quite different from the average between the two original half-maps. Also the automatic FSC curve will be very different from the deposited one. So in conclusion, despite what I say above, the most conservative thing would be to deposit the conventionally sharpened map as my main map and use the original half-maps for calculating the FSC-curve and use the 0.143 threshold from this curve to estimate the resolution. The DM map can be used during rebuilding/refinement, but I think final minimization should be against the main map during deposition (with restraints if the geometry gets worse). The DM map can be deposited as an auxiliary map. Do the community and the developers agree? Regards, Daniel 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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autogenerate restraint.eff from PDB for phenix.varref
by vincent Chaptal 18 Sep '23

18 Sep '23

Hi Phenix team, Before launching phenix.varref, I would like to generate a ligand restraint file so the ligand doesn't fly away from its density. It would be great if the ligand_restraints.eff file could be generated from a PDB file already containing the ligand (for example originating from refinement), that we can then edit afterwards. The ligand I'm talking about is ATP in this case, so it doesn't need external cif file for refinement. I searched but couldn't identify such a job. It would be useful if it could be added to "PDB tools" or similar. Thank Best Vincent -- Vincent Chaptal, PhD Director of GdR APPICOM Drug Resistance and Membrane Proteins Lab MMSB -UMR5086 7 passage du Vercors 69007 LYON FRANCE +33 4 37 65 29 01 http://www.appicom.cnrs.fr http://mmsb.cnrs.fr/en/

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racemic ligand refinement
by Calvin N Steussy 15 Sep '23

15 Sep '23

All, I need to refine a ligand that consists of two stereoisomers in my active site. I have decent density and have created models for the r and s forms of the guest with separate cif files. They have been fit independently into the active site density. My questions are; How to show these in the pdb file. Separate chains? Separate amino acids in a given chain? How do I keep them from interacting with one another during refinement? Creating an alt-position seems obvious but I'm not certain how to apply the different stereo restraints in that case. I'm sure someone has solved this before but I can't seem to find that information. Thanks, Nic Steussy Purdue University.

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Phenix workshop at 80th Pittsburgh Diffraction Conference (October 14, 2023)
by Pavel Afonine 14 Sep '23

14 Sep '23

Dear community, this is a reminder that we will be hosting a Phenix user workshop at 80th Pittsburgh Diffraction Conference on October 14, 2023 and there are still spaces available! https://web.cvent.com/event/03acbdbf-b2ae-4875-a16f-672346cf1fd1/summary This is a great opportunity to learn about latest and greatest features of Phenix, ask questions and seek expert advice on your specific problems. See you all there! All the best, Pavel

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Cis/trans peptide plane restraints ?
by CUNIASSE Philippe 13 Sep '23

13 Sep '23

Dear all, I am currently trying to refine a MDFF structure with the phenix RealSpaceRefine protocol of phenix. I am wondering if it is possible to apply systematic restraints to peptide plane (in trans when they are trans and cis when they are cis in order to avoid twisted conformations of the peptide planes at the end of the refinement. The only possibility I saw is to apply dihedral restraints defined one by one but when having thousands of residues, it seems not really convenient. Thanks in advance for your help. Best regards. Philippe. ----------------------------------------------- Philippe Cuniasse, PhD/HDR. Institut de Biologie Integrative de la cellule. UMR 9198 CNRS-CEA-Univ Paris Sud Bat 144 CE-Saclay 91191 Gif-sur-Yvette Cedex France Tel: (33) 1 69 08 56 35 Fax: (33) 1 69 08 47 12 Email: philippe.cuniasse(a)cea.fr<mailto:[email protected]> Web: http://biodev.cea.fr/rasmot3d/ [signature_863913621][signature_2053578832][signature_1816548304] -----------------------------------------------

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Re: [phenixbb] Command line phenix.sculpt_ensemble
by Randy John Read 11 Sep '23

11 Sep '23

Dear Matthew, Sorry, I somehow missed this for a few days. The first thing I would say is that I’m not sure there’s much of a use case for sculptor and ensembler (or the combined application you were using) in these days of AlphaFold. Sculpted ensembles were a really powerful way to combine information from a collection of distant homologues to make a better model for molecular replacement. However, since AlphaFold became available I think the current best approach in this scenario is to take the AlphaFold model (which will integrate everything known structurally about the class of proteins far better than ensembler), run it through process_predicted_model (to downweight or trim off the less reliable parts of the model) and use that single model as your molecular replacement model. I haven’t yet seen a counter-example where the experimental structures of the distant homologues are better. Of course, if someone has a counter-example that would be very interesting to learn about! In terms of this bug, I’m wondering whether it’s a Python compatibility issue. I’m guessing that your Mac might be one of the newer ones with ARM (M1 or M2) chips. If so, are you using a build for the older Intel processors, or the native ARM build? In any case, if you’re using the ARM build then this will be built with Python 3. The easiest way to tell is to go to a terminal window with Phenix set up and type: phenix.python --version This will report whether or not you’re using Python 2.7 or Python 3.7. The sculpt_ensemble procedure has a lot of options, and I would need to know exactly which options you had set in order to try to reproduce the problem. Could you look in the project directory for a file with a name like .phenix/project_data/sculpt_ensemble_NN.eff, where “NN” is the job number? If you could send me that file, that would help. Best wishes, Randy Read > From: Whitley, Matthew (NIH/NCI) [C] <matthew.whitley(a)nih.gov> > Date: Thu, Sep 7, 2023 at 10:54 PM > Subject: [phenixbb] Command line phenix.sculpt_ensemble > To: phenixbb(a)phenix-online.org <phenixbb(a)phenix-online.org> > > > Hello all, > I am trying to use the command line tool phenix.sculpt_ensemble to process a series of PDB files in preparation for molecular replacement. > However, when I run the following on the command line: > phenix.sculpt_ensemble 2*.pdb input.target_sequence=RRAS2.fasta > I get the following errors: > Traceback (most recent call last): > File "/Applications/phenix-1.21rc1-5015/build/../modules/phaser/phaser/command_line/sculpt_ensemble.py", line 84, in <module> > sculpt_ensemble.run( phil = params.phil, logger = logger ) > File "/Applications/phenix-1.21rc1-5015/modules/phaser/phaser/sculpt_ensemble.py", line 610, in run > logger = logger, > File "/Applications/phenix-1.21rc1-5015/modules/phaser/phaser/sculpt_ensemble.py", line 259, in read_in_target_sequence_files > for ( fname, i ) in itertools.zip_longest( filenames, range( 1, nchains + 1 ) ): > AttributeError: 'module' object has no attribute 'zip_longest' > I am running phenix 1.21rc1-5015-000 on Mac OS 13.5.1. > Any ideas? > Thanks, > Matthew > _______________________________________________ > phenixbb mailing list > phenixbb(a)phenix-online.org > http://phenix-online.org/mailman/listinfo/phenixbb > Unsubscribe: phenixbb-leave(a)phenix-online.org ----- Randy J. Read Department of Haematology, University of Cambridge Cambridge Institute for Medical Research Tel: +44 1223 336500 The Keith Peters Building Hills Road E-mail: rjr27(a)cam.ac.uk Cambridge CB2 0XY, U.K. www-structmed.cimr.cam.ac.uk

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Command line phenix.sculpt_ensemble
by Whitley, Matthew (NIH/NCI) [C] 07 Sep '23

07 Sep '23

Hello all, I am trying to use the command line tool phenix.sculpt_ensemble to process a series of PDB files in preparation for molecular replacement. However, when I run the following on the command line: phenix.sculpt_ensemble 2*.pdb input.target_sequence=RRAS2.fasta I get the following errors: Traceback (most recent call last): File "/Applications/phenix-1.21rc1-5015/build/../modules/phaser/phaser/command_line/sculpt_ensemble.py", line 84, in <module> sculpt_ensemble.run( phil = params.phil, logger = logger ) File "/Applications/phenix-1.21rc1-5015/modules/phaser/phaser/sculpt_ensemble.py", line 610, in run logger = logger, File "/Applications/phenix-1.21rc1-5015/modules/phaser/phaser/sculpt_ensemble.py", line 259, in read_in_target_sequence_files for ( fname, i ) in itertools.zip_longest( filenames, range( 1, nchains + 1 ) ): AttributeError: 'module' object has no attribute 'zip_longest' I am running phenix 1.21rc1-5015-000 on Mac OS 13.5.1. Any ideas? Thanks, Matthew

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Phenix presentation at IUCr Melbourne Software Fayre
by Dorothee Liebschner 25 Aug '23

25 Aug '23

Hi everyone, For those of you attending the IUCr conference in Melbourne, please note the following presentations at the Software Fayre. Talks in the Software Fayre are unfortunately not listed in the conference app, so I advertise it here. "Phenix - Macromolecular structure determination using crystallographic and cryo-EM data" (*Dorothee Liebschner*) When: Saturday, 8/26, 12:45 - 13:30pm Where: Room 214 Topics include: - Introduction to Phenix - What's new - Using predicted models for Crystallography "Physics-based macromolecular model building with ISOLDE" (*Tristan Croll*) When: Saturday, 8/26, 14:15 - 15:00 pm Where: Room 214 Best wishes, Dorothee -- Research Scientist, Molecular Biophysics and Integrated Bioimaging Lawrence Berkeley National Laboratory 1 Cyclotron Road, M/S 33R0345 Berkeley, CA 94720 Tel: (510) 486-5709 Fax: (510) 486-5909 Web: https://phenix-online.org

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Generation of residual electron density maps using IAS (inter atomic scatteres) model
by Ankur Kumar Singh 08 Aug '23

08 Aug '23

Dear Members, I am working on a protein structure resolved at 1.1 angstroms, and I am trying to generate a residual electron density map. I am following a series of articles from Prof. Afonine (Macromolecular refinement at subatomic resolution with interatomic scatterers<https://pubmed.ncbi.nlm.nih.gov/18007035/>). Here, an IAS modeling of the protein structure is done, followed by refinement in Phenix. The residual density is observed in conventional maps. I am trying to figure out how to create an IAS model for my protein structure. Please suggest any relevant method/article to obtain the model. And also, is it possible to have an IAS model for a protein resolved at 1.1 angstroms? Many thanks for considering my request. ----- Regards, Ankur K Singh Graduate Student

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General interest: Data matters session at the ACA 2023 in Baltimore
by John R Helliwell 05 Aug '23

05 Aug '23

Dear Colleagues, I have placed a note about this at the IUCr Committee on Data Public Forum: https://forums.iucr.org/viewtopic.php?f=39&t=457&sid=54ca94b6a4db968acc28ab… including a weblink to my slides at Zenodo. Best wishes, John Emeritus Professor John R Helliwell DSc

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