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Appplying symmetry to a Cryo-EM map in phenix map_to _model
by Joshua Jude Lobo 11 Aug '17

11 Aug '17

Hi Phenix Group I am very new to model building and using phenix . I am trying to use phenix.map_to_model to generate a model just using my cryo-EM map( mrc format) and a fasta sequence .My protein has octahedral symmetry . I found the use_space_group_symmetry argument but am not sure what argument to give to impose the symmetry . Any inputs are appreciated Sincerely Joshua Lobo University of Minnesota Twin Cities

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seeking advice on how to configure Phaser-MR (full-featured) to use a previous partial solution
by Emilia C. Arturo (Emily) 08 Aug '17

08 Aug '17

Hello. I have a 3-domain protein (let's say it's organized from N to C as A-B-C) whose structure I am working to determine now. Although several single- (A alone, B alone), double- (A+B and B+C) and 3-domain (A+B+C) structures of this protein (from a different organism whose primary sequence is, overall, ~85% identical to the one on which I'm working) have already been determined and deposited in the PDB, I would ideally like to use a minimal probe (i.e. as few domains as possible) in order avoid model bias that could be imposed on the relative orientation of domains A, B, and C. So far, I have phase solutions (TFZ scores for all in the high-50s and 60s) using B-only, A+B, and B+C pdb files as probes. A-only structures have not given a phase solution (TFZ is ~7 and autobuild gives a solution that looks unbelievable in Coot), perhaps because A is relatively small in size. Here is my problem: I suspect that A and B sit relative to one another in an interesting way in this particular structure, so I'd like to use Phaser to search for a solution given the fixed partial solution from a B-only search, together with an A-only structure as a separate probe. So far no MR solutions have been found when I configure the run with an A-only pdb file and a B-only-derived Phaser result that is input as a fixed partial solution. I'm writing to ask for advice on how to configure the search. I think that the problem is my configuring the search, and not that a solution cannot be found from these coordinates. This is the reason I think that my problem is in configuring the search; please correct me if I'm wrong: Using a Phaser result derived from using an A+B structure as probe, I cut up the resulting pdb file into 2 pdb files - one containing an A' and another containing a B', where A' is the A domain of the Phaser result, and B' is the B-only part. Then I configured a Phaser result with B' as an ensemble that is a fixed partial solution, and A' as a separate ensemble/probe. I searched for 4 of each since 4 chains is the most likely composition in the ASU. I expected to get a result similar to what Phaser calculated when I input the A+B structure as an intact probe. Instead of getting a solution where 4 A+B chains were placed as they were in the first Phaser result, which gave one solution with a TFZ score of 65, I got 13 solutions, the top scoring a TFZ of 7.5, and each solution having a total of 9 chains - 4 As and 5 Bs. Is anyone willing to help me troubleshoot the above before I throw up my hands and settle on either manually building two domains onto the single-domain solution, or one domain onto the 2-domain solution, keeping in mind the potential for model bias? I am keen on using the B-only solution as a fixed partial solution to place domain A because all the B-only structures provide coordinate information for a portion of domain B that is unresolved in any of the multi-domain structures that contain domain B. I am using the Phenix gui, version 1.12rc1-2807. Regards, Emily. -- "Study as if you were going to live forever; live as if you were going to die tomorrow." - Maria Mitchell "I'm not afraid of storms for I'm learning to sail my ship." - Louisa May Alcott

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Very low rmsd bond length
by Mark Saper 07 Aug '17

07 Aug '17

Hi all, A reviewer points out that my refined structures (which have already been deposited in PDB) have very small RMSD values for bond lengths (0.005–0.002) (refinement resolutions are 2.0–2.8 Å), and that my weights should be decreased. The weights were calculated with “Optimize XYZ Weight” option turned ON. This seems to be the case with all of the structures that I have refined during the past 5 years. My impression from previous discussions is that deriving explicit weights from these optimized ones is not straightforward and so I have never tried to relax the weights. Moreover inspecting the optimization results in the log file, suggest that changing the weights to increase the RMSD would increase the Rfree. (I can post this if its helpful). How do I address the reviewer’s concerns? Thanks, Mark _______________________________________________ Mark A. Saper, Ph.D. Associate Professor of Biological Chemistry, U-M Medical School Room 3220B, MSRB III saper(a)umich.edu +1 (734) 764-3353

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Comput. Cryst. Newsl. (2017) 2
by Nigel Moriarty 04 Aug '17

04 Aug '17

The latest Computational Crystallography Newsletter is available for download. Below is the clickable table of contents. July 2017 <https://www.phenix-online.org/newsletter/CCN_2017_07.pdf> Short Communications - phenix.mtriage: a tool for analysis and validation of cryo-EM 3D reconstructions <https://www.phenix-online.org/newsletter/CCN_2017_07.pdf#page=6> - More TLS validation with phenix.tls_analysis <https://www.phenix-online.org/newsletter/CCN_2017_07.pdf#page=8> Fitting tips #14 – How Ser & Thr behave oddly on helices <https://www.phenix-online.org/newsletter/CCN_2017_07.pdf#page=2> Cheers Nigel --- Nigel W. Moriarty Building 33R0349, Molecular Biophysics and Integrated Bioimaging Lawrence Berkeley National Laboratory Berkeley, CA 94720-8235 Phone : 510-486-5709 Email : NWMoriarty(a)LBL.gov Fax : 510-486-5909 Web : CCI.LBL.gov

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mrc to mtz conversion to open map in coot
by Joshua Jude Lobo 03 Aug '17

03 Aug '17

Hi phenixbb I am new to phenix and am trying to convert a cryo-em map(mrc format) to mtz format using the phenix.map_to_structure_factors command .This proceess finishes without errors but the resultant mtz file is not viewable in coot . I have tried both the phenix.map_to_model and the phenix.map_to_model_histogram_1.12-2829 How is the best way to troubleshoot this ? Any inputs would be appreciated Sincerely Joshua Lobo University of Minnesota Twin Cities

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Berkeley servers are back in service
by Billy Poon 03 Aug '17

03 Aug '17

Hi everybody, The servers at Berkeley are now available. Please let us know of any 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 Tel: (510) 486-5709 Fax: (510) 486-5909 Web: https://phenix-online.org

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Lab Evac
by Nigel Moriarty 03 Aug '17

03 Aug '17

Folks The Grizzly Fire (the media loves a interesting name) is more than 50% contained and the lab is now open. The servers are, once again, available for downloading the latest version of Phenix, 1.12. Cheers Nigel --- Nigel W. Moriarty Building 33R0349, Molecular Biophysics and Integrated Bioimaging Lawrence Berkeley National Laboratory Berkeley, CA 94720-8235 Phone : 510-486-5709 Email : NWMoriarty(a)LBL.gov Fax : 510-486-5909 Web : CCI.LBL.gov

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Emergency shutdown
by Nigel Moriarty 02 Aug '17

02 Aug '17

Folks Phenix servers are shutting down due to a grass fire in the area. Cheers Nigel --- Nigel W. Moriarty Building 33R0349, Molecular Biophysics and Integrated Bioimaging Lawrence Berkeley National Laboratory Berkeley, CA 94720-8235 Phone : 510-486-5709 Email : NWMoriarty(a)LBL.gov Fax : 510-486-5909 Web : CCI.LBL.gov

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Postdoctoral position in Structure and Function of Fungal Membrane Proteins
by Maike Bublitz 02 Aug '17

02 Aug '17

Postdoctoral position in Structure and Function of Fungal Membrane Proteins A post-doctoral position is available in the research group of Associate Prof. Maike Bublitz at the Department of Biochemistry, University of Oxford. The project aims to understand the structure and function of fungal membrane transport proteins identified as potential new drug targets, using a combination of state-of-the-art structural (X-ray crystallography, cryo-EM) and biochemical/biophysical techniques. Applicants should hold a PhD in a relevant subject area, such as membrane protein biochemistry or structural biology. Experience in native or recombinant membrane protein expression, purification and either structural determination or functional analysis using biochemical and biophysical techniques is essential. Ability to work in a team as well as contribute to supervision activities and excellent verbal and written communication skills are expected. Experience in protein X-ray crystallography and/or cryo-EM is an advantage. To apply for this role and for further details, including the job description and selection criteria, please click on the link below: https://www.recruit.ox.ac.uk/pls/hrisliverecruit/erq_jobspec_details_form.j… Applications for this vacancy are to be made online by 31th August 2017.

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(no subject)
by Priyanka Abeyrathne 21 Jul '17

21 Jul '17

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