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Few questions about the model building and refinement of cryo-EM data
by Wang, Bing 28 Aug '17

28 Aug '17

Hi guys, Sorry for the detailed questions from a beginner! I am starting a modeling/refinement work for a set of cryo-EM data. Data basic information: phage data (looks like a ball with P1 space group), map size ~870 MB, resolution ~6 A, two X-ray structures for model building General strategies: I select COOT for the model building; using phenix.real_sapce_refine for the real space refinement with secondary structure restrain and REFMAC for the reciprocal space refinement. Few questions are listed here. 1. The map was too bigger to open it in COOT. The phenix.map_to_structure_factors was used to obtaine ~120 MB sized MTZ file (still a little big for my computer). I manually build up the whole ball-shaped phage with the rigid body fit in COOT (from two X-ray structures to 120 chains). My first question will be: In this case, should I crop the map in Chimera or other software and only focus on a small asymmetric unit to do the model building and the followed refinement. 2. I would like to do a real space refinement after the model building. Input files: A pdb file I just built up from COOT A original MAP file A transfered MTZ file Two restraint files from two X-ray structures by ProSMART (TXT formart) The refinement parameters I would like to select in GUI interface: minimization_global, rigid_body, local_grid_search, adp Use secondary structure restraints Reference model restraints: use starting model as reference, main chain, side chain, fix outliers, secondary structure only Rotamer restraints Ramachandran restraints Show per residue My second set of questions: Should I select the MAP file (~870 MB) or the MTZ file (~120 MB)? Is that necessary to add the two restraint files from ProSMART if I use the starting model as reference? Is the refinement parameters selected properly? 3. I gave a try by phenix.real_space_refine. An first error showed up: Number of atoms with unknown nonbonded energy type symbols: 6840 "ATOM 184 HG1 SER 1 12 .*. H " "ATOM 458 HG1 SER 1 30 .*. H " "ATOM 699 HG1 SER 1 45 .*. H " "ATOM 720 HG1 SER 1 47 .*. H " "ATOM 762 HG1 SER 1 50 .*. H " "ATOM 1241 HG1 SER 1 81 .*. H " "ATOM 1465 HG1 SER 1 95 .*. H " "ATOM 1747 HG1 SER 1 113 .*. H " "ATOM 1758 HG1 SER 1 114 .*. H " "ATOM 2173 HG1 SER 1 141 .*. H " ... (remaining 6830 not shown) I tried phenix.ready_set to fix this problem according to a previous discussion but it gave me another error: ENDMDL record missing at end of input. Thus my third question will be how to fix the first error? Thank you for patience! I would really appreciate your help! Bing

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Opening phenix X-ray/neutron maps in Coot without the Phenix GUI
by Derek Logan 23 Aug '17

23 Aug '17

Hi ccp4bb and phenixbb, Is there a convenient way to open MTZ files in Coot that are the result of joint X-ray/neutron refinement in phenix.refine, but where phenix.refine was run in command-line mode? I would like achieve what is done in the Phenix GUI at the click of a button, i.e. open Coot with the structure and 2Fo-Fc and Fo-Fc maps for both neutron and X-ray. At the moment I have to open each MTZ file four times in the Coot GUI, once for each type of map. Is there a script buried somewhere in the Phenix installation that can be modified? /Derek ________________________________________________________________________ Derek Logan tel: +46 46 222 1443 Associate Professor mob: +46 76 8585 707 Dept. of Biochemistry and Structural Biology www.cmps.lu.se<http://www.cmps.lu.se> Centre for Molecular Protein Science bit.ly/2d0HxmS Lund University, Box 124, 221 00 Lund, Sweden

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Master Your Proteins, NKI Amsterdam, 20-23 November 2017
by Anastassis Perrakis 18 Aug '17

18 Aug '17

Dear all, Applications for the Instruct-ERIC course on Biophysical Characterisation of Macromolecules and Quantification of Biomolecular Interactions are now open. The course aims to provide the theoretical background of popular biophysical methods that are often used in relation to Structural Biology research, and practical experience both in performing experiments and in analysing the resulting data. The rationale behind an extended kit of experiments to characterise macromolecules and their interactions will be explained. You will be shown how to perform and analyse the related experiments in dedicated practical sessions. The course will include theory and practical sessions on thermal shift assays (also label free), Surface Plasmon Resonance, sothermal Titration Calorimetry, Miscroscale Thermophoresis , Fluoresence Methods, Stopped Flow, and the Graphpad/Prism and Kintek analysis software. Details can be found at: https://www.structuralbiology.eu/events/biophysical-characterisation-of-mac… <https://www.structuralbiology.eu/events/biophysical-characterisation-of-mac…> On the behalf of the organisers, Tassos

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Macromolecular Crystallography workshop in South America
by Alejandro Buschiazzo 17 Aug '17

17 Aug '17

Dear colleagues, We are pleased to announce our sixth edition of the Workshop: Macromolecular Crystallography School "From data processing to structure refinement and beyond", to be held at the Institut Pasteur de Montevideo (Uruguay). http://pasteur.uy/mx2017 Dates: November 13 - 23, 2017 Confirmed speakers and tutors (so far... a few more may join the crew): Alejandro Buschiazzo, Montevideo, Uruguay Paul Emsley, Cambridge, UK Richard Garrat, São Carlos, Brazil Ronan Keegan, Oxford, UK Eugene Krissinel, Oxford, UK Andrey Lebedev, Oxford, UK Andrew Leslie, Cambridge, UK Garib Murshudov, Cambridge, UK Colin Palmer, Oxford, UK James Parkhurst, Oxford, UK Randy Read, Cambridge, UK Clemens Vonrhein, Cambridge, UK Please find the program of the Workshop, the application form and further contact information, at http://pasteur.uy/mx2017 (this www site will be updated regularly, so stay tuned!) This Workshop is supported by the Collaborative Computational Project Nº4 (CCP4, UK) & Science and Technology Facilities Council (UK); the Centro de Biologia Estructural del Mercosur (CeBEM); the International Union of Crystallography (IUCr); and the Institut Pasteur de Montevideo. Organizers: Alejandro Buschiazzo, PhD. Institut Pasteur de Montevideo, Uruguay Ronan Keegan, PhD. CCP4, STFC Rutherford Appleton Laboratory, United Kingdom Richard Garratt, PhD. Instituto de Fisica de Sao Carlos, USP, Brazil Applicants: 24 students will be selected, aiming at advanced PhD, postdocs and young researchers. The Course will provide financial support covering registration fees, and for the case of those students coming from abroad, all local expenses (lodging, per diem and local transportation). Look in the www site for details on application procedures. The application deadline is September 17, 2017. Please address further inquiries to: mx2017(a)pasteur.edu.uy Looking forward to welcoming you in Montevideo! -- Alejandro Buschiazzo, PhD Associate Professor Laboratory of Molecular & Structural Microbiology Institut Pasteur de Montevideo Mataojo 2020 Montevideo 11400 URUGUAY Phone: +598 25220910 int. 120 Fax: +598 25224185 http://pasteur.uy/en/laboratorios-eng/microbiologia-estructural-y-molecular…

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Postdoctoral position at the University of Chicago
by Robert Keenan 15 Aug '17

15 Aug '17

The Keenan lab at the University of Chicago has an opening for a postdoctoral scientist to study the structure and function of protein complexes involved in membrane protein biogenesis and quality control. Applicants should be nearing completion of a PhD in structural biology and have a strong academic record with significant publications. Experience in molecular biology, protein purification and electron microscopy/x-ray crystallography is required. To apply, please send a CV and a short statement describing your motivation for wanting to join the lab. Please be prepared to arrange for three letters of reference to be sent by email. For more information, please visit our webpage: http://keenanlab.bsd.uchicago.edu

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Phenix.real_space_refine
by Reza Khayat 11 Aug '17

11 Aug '17

Hi, I am refining a virus into an image reconstruction and have been having issues using the NCS capability of phenix.real_space_refine_1.12-2829. I think it may be my misunderstanding of the manual. The virus has 60subunits and I am feeding phenix a complete oligomer. I manually modify the first subunit with coot (simple movements and such), define an NCS group file where the first subunit is the reference and the other 59 are selection, and feed these into phenix.real_space_refine. Does phenix recapitulate my modifications of the first subunit into the remaining 59 subunits to create an oligomer that contains all my modifications before starting refinement? Reza Khayat, PhD Assistant Professor City College of New York Department of Chemistry New York, NY 10031

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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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