- phenixbb - phenix-online.org

The experiment is still very much needed (though AlphaFold helps a lot)
by Tom Terwilliger 01 Dec '23

01 Dec '23

Hi Structural biologist colleagues! Our article that helps you make the case that the experiment is still very much needed is now out: https://www.nature.com/articles/s41592-023-02087-4 "AlphaFold predictions are valuable hypotheses and accelerate but do not replace experimental structure determination." Nature Methods (2023) Also, here is a video on the Phenix Tutorials YouTube channel that describes this analysis: https://www.youtube.com/watch?v=ugMPYdPo8Bc (I hope you will be happy to see that you and your structural biology colleagues get the credit for making AlphaFold possible at 2:35 in the introduction of this video! Keep up the fantastic structural biology work!) All the best, Tom T -- Thomas C Terwilliger Laboratory Fellow, Los Alamos National Laboratory Senior Scientist, New Mexico Consortium 100 Entrada Dr, Los Alamos, NM 87544 Email: tterwilliger(a)newmexicoconsortium.org Tel: 505-431-0010

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Possible problem with eLBOW in version 1.21rc1.5058 using smiles string
by Francisco Javier Medrano 30 Nov '23

30 Nov '23

Dear developers: I have tried to use eLBOW in version 1.21rc1.5058 to generate a cif file for a ligand and the program give me the following error: SMILES parser error:"Unable to load parsing table". The smiles string used was OP(OP(O)(O)=O)(O)=O, but it does not work for other strings. It does work if you supply a pdb file with connect records. If I use version 1.20.1-4487 with the same smiles string it does work properly. Is there any bur in the 1.21 version? Best regards -- Fº Javier Medrano Cristalografía de Macromoléculas Centro de Investigaciones Biológicas Margarita Salas C/ Ramiro de Maeztu, nº 9 Madrid - Spain

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issue with restrains
by Dmitry Semchonok 22 Nov '23

22 Nov '23

Dear colleagues, The issue with the refinement (Phenix 1.21rc1-5130) The refinement does not recognize the phil parameters prepared with ReadySet. [cid:5bb12054-9715-417b-a68d-58c1228ffe56] Please prompt me on how to proceed. Thank you Kins regards, Dmitry

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Errors in atomic coordinates and B factors in MX
by John R Helliwell 20 Nov '23

20 Nov '23

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Question about phenix.resolve_cryo_em
by Reza Khayat 19 Nov '23

19 Nov '23

Hi, Is it possible to turn off the model refinement procedure in phenix.resolve.cryo_em and go straight into density modification? My current model fits reasonably well. Also, Does the routine work well with nucleic acid (e.g. something like RNA from ribosome)? Best wishes, Reza

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EM difference map calculation
by Leonid Sazanov 14 Nov '23

14 Nov '23

Hi, I have tried to use this command in 1.21rc1-4933: phenix.real_space_diff_map XXX.pdb XXX_box.ccp4 resolution=3.0 Model was real-space refined against _box map and the result with map_model_difference_1.ccp4 looks more or less as expected, except that at medium to low density levels strong cubic shape artifacts start to appear. I thought that might be because _box.ccp4 map is not cubic, but re-running with the original cubic map gives even stronger artifacts. Is this a known issue and how this might be resolved? Or perhaps this functionality now comes in one of the newer tools? Many thanks! Leonid -- Prof. Leonid Sazanov FRS IST Austria Am Campus 1 A-3400 Klosterneuburg Austria Phone: +43 2243 9000 3026 E-mail: sazanov(a)ist.ac.at

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Exclude Waters from order_solvent=true updates
by Schulz, Dr. Eike 14 Nov '23

14 Nov '23

Hello everyone, I am refining a few structures via a bash script using constrained occupancy refinement by providing a parameter file. I am trying to model the occupancy of a ligand and the water molecules in its vicinity. This works generally well, but as soon as I switch on ordered_solvent=true, these water molecules are also filtered / updated and eventually removed. How can I avoid this ? That is specifically excluding a number of water molecules from being updated ? With best regards, Eike

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Automated estimation of voxel size using reference pixel size in phenix?
by Oliver Clarke 13 Nov '23

13 Nov '23

Hi, In cryoEM, the pixel size is often not known with certainty, and we need to calibrate it by measuring the real space correlation of a reference crystal structure of a component at different nominal pixel sizes. Currently we do this manually, using `fitmap` in UCSF Chimera, but given the sophisticated set of tools in Phenix for fitting atomic models and analyzing real space correlations, I was wondering if a tool in Phenix already exists to do this, or whether there would be any interest in adding such a tool at some point? Cheers Oli

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an atom moves away during model refinement
by Dmitry Semchonok 07 Nov '23

07 Nov '23

Dear colleagues, While refining my model, the Mg atom for some of the margin units moves far away from them. I am also using the ELBOW files of Mg during the refinement. What is the way to restrict the movement of atoms during refinement? I found that this behaviour can be observed after simulated annealing is on. And the harmonic_restraints may be acquired to restrict atom movement. Is that right? I am using the GUI version of Phenix, and I cannot see those parameters. Thank you. Sincerely, Dmitry

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phenix.real_space_diff_map - difference between output maps
by Jose Artur Brito 31 Oct '23

31 Oct '23

Dear All, I am trying to use phenix.real_space_diff_map to assess "reminiscent" density in a 1.9 A cryoEM map. Can someone explain the difference between map_model_difference_1.ccp4 and map_model_difference_2.ccp4 that PHENIX outputs? Thanks in advance, best, Jose --

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