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how to inhibit selectively undue H....O repulsion during refinement with phenix.refine ?
by Maxime Cuypers 10 Feb '18

10 Feb '18

Hello, i am refining neutron data with hydrogens on water molecules complexes that systematically bounce the whole molecule away from the hydroxyls or carboxylic groups or other waters. the Fo-Fc map is crystal clear about where the H atoms should go... any commands i can enter in i.e. a .param file to inhibit repulsion and promote closer h bonds? thanks for your help, cheers, Dr. Maxime Cuypers Post-Doctoral Research Associate, Structural Biology St Jude Children s Research Hospital, 262 Danny Thomas Place Memphis, TN 38105-3678, USA

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query re local grid search in phenix.real_space_refine
by Oliver Clarke 10 Feb '18

10 Feb '18

Hi all, Related to the last message - when using local_grid_search, does phenix attempt to torsion-angle search every residue, or just outliers? It would seem like maybe using EMRinger or similar to identify residues where there is strong sidechain density, but in a non-rotameric position or with an incorrectly fit rotamer might be one way to make it more efficient if it is the former. I don’t want phenix trying to do a local grid search on residues with no sidechain density - these may be in an area of the map with poor local resolution, perhaps where I have docked a crystal structure, or carefully manually adjusted rotamers - local grid search in these regions is likely to make things worse if it is not focused on residues with clear sidechain density. Cheers Oli

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parallelization of local_grid_search in phenix.real_space_refine?
by Oliver Clarke 10 Feb '18

10 Feb '18

Hi all, phenix.real_space_refine runs pretty decently with run=minimization_global+adp, and the adp part is already parallelized. Using local_grid_search though, it slows down enormously, particularly for large structures, and I’d really like to try using it to correct poorly fit rotamers. Is there any prospect for parallelizing this function? Naively it seems like something that might be amenable to parallelization - so long as adjacent local grids aren’t searched at the same time, it would seem like one might be able to split up the job to run on multiple threads? These days a lot of folks have GPU workstations for cryoEM, which often (in addition to GPUs) have Xeon or Threadripper CPUs with many cores - I’d love to be able to use that computational horsepower effectively for refining my structures. Cheers Oli

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Phenix.molprobity PDB pre-test
by Rune Thomas Kidmose 09 Feb '18

09 Feb '18

Hi, After using Phenix.molprobity I noticed it does a test of the input PDB file in the beginning, where it, among other things, identifies duplicate atom labels and then proceeds to list some of them (and hides the rest some where I guess). It also identifies mismatches between the atom label and the atom type, e.g. if a CB is by mistake listed as an O instead of a C, in the last column in the PDB file. I would like to know if it is possible to somehow call this PDB pre-test function used within phenix.molprobity? or maybe something similar in the phenix package? I would like to use the feature in a small MD pipeline I am developing where the input PDB files are checked for duplicate atoms and mismatches between atom label and type. I believe something like the mentioned pre-test feature would work much better, than my current bash script solutions using combinations of awk, grep, sort, uniq etc. Cheers Ruki

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clashscore
by 潘晓伟 09 Feb '18

09 Feb '18

Hello everyone I refine a cryo EM data with 3.1 angstrom, the model fit well with the map, but the clashscore is high, abot 23. How can I decrease the value of clashscore with realspace.refinement in Phenix GUI. Thanks! Pan ________________________________ xiaowp82(a)hotmail.com

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Computational Crystallography Newsletter, Volume 9, Number 1
by Nigel Moriarty 08 Feb '18

08 Feb '18

I am pleased to announce the publication of the latest issue of the Computational Crystallography Newsletter: http://www.phenix-online.org/newsletter/ A listing of the articles and short communications is given below. Please note that the newsletter accepts articles of a general nature of interest to all crystallographers. Please send any articles to me at NWMoriarty(a)lbl.gov noting that there is a Word Template on the website to streamline production. January 2018 <http://phenix-online.org/newsletter/CCN_2018_01.pdf> Articles - Cβ deviations and other aspects in Amber versus CDL refinements <http://phenix-online.org/newsletter/CCN_2018_01.pdf#page=21> - A few benchmark tests of various compilers on Linux and Windows <http://phenix-online.org/newsletter/CCN_2018_01.pdf#page=25> Short Communications - Tools for model-building with cryo-EM maps <http://phenix-online.org/newsletter/CCN_2018_01.pdf#page=7> - Gemmi – a new MX library <http://phenix-online.org/newsletter/CCN_2018_01.pdf#page=13> - Overfitting to Ramachandran and geometry criteria in the cryoEM Model Challenge <http://phenix-online.org/newsletter/CCN_2018_01.pdf#page=16> Fitting tips #15 – New help to make your 2.5–4Å cryoEM structure even better <http://phenix-online.org/newsletter/CCN_2018_01.pdf#page=2> FAQ - What happens when the Phenix GUI prompts me to send an error report? <http://phenix-online.org/newsletter/CCN_2018_01.pdf#page=6> 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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Residual B values after refinement
by ANAN YUENYAO 07 Feb '18

07 Feb '18

Dear All, I have encountered some error during the PDB validation process after refinement with PHENIX (1.13). After uploading the coordinates and structure factor file, in the header 'Basic coordinate validity', it says that the data contains residual B values. Could anyone please explain the reason behind this error message. Is it going to be problematic for the future PDB deposition? P.S. I have already performed TLS and group B-factor refinement. Thank you in advance! Anan

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FASTA format for sequence file
by egoers＠uoregon.edu 06 Feb '18

06 Feb '18

Hello, I'm trying to run Phase-MR on Phenix (older version) and having trouble formatting my sequence properly. I keep getting error "Protein Sequence not recognized in Composition". I have a good idea of what FASTA should look like (carrot with a name, no spaces or weird characters, followed by the sequence in all capital letter on the next line). I have tried many things, mainly using gedit and plain text files (.txt). I've made sure the file name doesn't have any strange characters as well. If I cut and paste a FASTA file from the PDB into gedit, save that at a .txt, Phaser accepts it. If I cut and paste my protein sequence into the same file, it rejects it. Suggestions?

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how to bypass/deactivate dictionnary check for restraints in phenix.refine
by Maxime Cuypers 02 Feb '18

02 Feb '18

Hello All, I am refining an unusual complex moiety in a protein xl with neutron data. Does anyone know if it is possible to bypass/deactivate dictionnary .cif check i got the blocking error message "it looks like angle and bond restraints are conflicting." and Phenix.refine stops. but really it s not conflicting: my .cif file works great in coot to model the complex. it is hydrogen based, so i really need restraints to get it optimal. any clues welcome, many thanks in advance. Dr. Maxime Cuypers Post-Doctoral Research Associate, Structural Biology St Jude Children s Research Hospital, 262 Danny Thomas Place Memphis, TN 38105-3678, USA

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side-chain on special position.
by Aaron Oakley 02 Feb '18

02 Feb '18

Hello fellow Phenix-ers, I have a structure I am trying to finish in Phenix.refine The is one problem: a glutamate residue sitting on a crystallography 2-fold axis with partial occupancy (picture attached). This residue and its symmetry mate appear to take turns sitting at this position: filling the density leads to severe collision with its symmetry mate. Building the side-chain with occupancy 0.5 doesn’t seem to help, as the residue is pushed out of density during refinement. Any work-arounds? Thanks all, Aaron [cid:[email protected]]

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phenix auto sharpen local sharpening masking artifacts?
by Oliver Clarke 01 Feb '18

01 Feb '18

Hi, I’m trying to run phenix.auto_sharpen with local sharpening, because I have an EM map that has a reasonably substantial variation in local resolution. This is the command I used: phenix.auto_sharpen cryosparc_exp001049_008.mrc resolution=3.26 local_sharpening=true local_aniso_in_local_sharpening=true model.pdb nproc=4 seq_file=seq.fasta >& log & The resulting map looks beautiful (maybe a little too beautiful??) around the model, but shows some funky looking masking artifacts in the density further away from the model (in the micelle region) - see screenshot. Am I doing something wrong? And can I trust that the density is completely free of model bias? Cheers Oli

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Unwanted LINK Records
by Whitley, Matthew J 26 Jan '18

26 Jan '18

Hello all, I am currently refining a structure using Phenix 1.13-2998. Present in this structure is a diphosphate-containing ligand. In the protein chain surrounding the binding site, there is an arginine side chain that points generally toward the diphosphate group, but I cannot define the specific location of the side chain because the side chain density is very poor. The density for the ligand is unambiguous. Upon refinement, Phenix places the Arg side chain so close to the ligand that it draws a covalent bond between the two, and the post-refinement PDB file contains a LINK record for this bond. In reality, the two are not covalently connected, and ideally Phenix would find a conformation for this side chain that is outside of covalent bonding distance. I have tried refining after manually moving the side-chain to a non-clashing position multiple times, but in every case the output PDB contains a LINK for a covalent bond between ligand and side chain. My question: How can I tell Phenix NOT to allow these atoms to come with covalent bonding distance? Is there some kind of "anti-LINK" information I can feed it that will force phenix.refine to select some other conformation for the side chain? Thanks for your advice. Sincerely, Matthew Whitley --- Matthew J. Whitley, Ph.D. Research Instructor Department of Pharmacology & Chemical Biology University of Pittsburgh School of Medicine

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Open Research Positions: Structural Biophysics of Protein Allostery, in New York City
by Daniel Keedy 26 Jan '18

26 Jan '18

The Daniel Keedy Lab at the ADVANCED SCIENCE RESEARCH CENTER (ASRC) AT CUNY in New York City has available positions for a POSTDOCTORAL SCHOLAR and a LABORATORY TECHNICIAN starting in 2018. The lab’s goal is to elucidate the role of protein flexibility in allosteric regulation — and to use that knowledge to control the function of dynamic, biomedically important enzymes such as tyrosine phosphatases. To do so, we combine cutting-edge experimental and computational techniques in structural biology, including multitemperature X-ray crystallography, high-throughput protein:ligand structure determination, and new algorithms for modeling alternative protein conformations based on electron density maps. REQUIREMENTS FOR THE POSTDOCTORAL SCHOLAR POSITION: a PhD in structural biology, biophysics, computational biology, or a related field; multiple years of experience studying proteins or other macromolecules; and excitement to try new techniques at both the bench and the keyboard. Familiarity with X-ray crystallography, a programming language, and the command line are preferred. REQUIREMENTS FOR THE LABORATORY TECHNICIAN POSITION: an MS, BS, or similar degree in biochemistry, molecular biology, or a related field; experience conducting research in a laboratory setting; and excellent organizational and communication skills. Experience with cloning, protein purification, and/or X-ray crystallography are preferred. OFFICIAL APPLICATIONS: For the postdoctoral scholar position, please apply here: https://cuny.jobs/new-york-ny/research-associate-structural-biology-advance… For the laboratory technician position, please apply here: https://cuny.jobs/new-york-ny/research-assistant-laboratory-technician-stru… ABOUT THE ASRC: The ADVANCED SCIENCE RESEARCH CENTER (ASRC) at the Graduate Center of the City University of New York (CUNY) elevates scientific research and education at CUNY through initiatives in five distinctive, but increasingly interconnected disciplines: STRUCTURAL BIOLOGY, NANOSCIENCE, PHOTONICS, NEUROSCIENCE, and ENVIRONMENTAL SCIENCES. The ASRC promotes a collaborative, interdisciplinary research culture with researchers from each of the initiatives working side-by-side in the ASRC’s core facilities, sharing equipment that is among the most advanced available. The ASRC is next-door to the cutting-edge inter-institutional NEW YORK STRUCTURAL BIOLOGY CENTER (NYSBC), and is also just 70 miles from the newly-constructed NATIONAL SYNCHROTRON LIGHT SOURCE II (NSLS-II), now the brightest synchrotron light source in the US. — Daniel A. Keedy, Ph.D. Assistant Professor Structural Biology Initiative, CUNY Advanced Science Research Center Department of Chemistry and Biochemistry, City College of New York Biochemistry and Chemistry Ph.D. Programs, CUNY Graduate Center http://www.keedylab.com // daniel.keedy(a)asrc.cuny.edu<mailto:[email protected]> // 212-413-3246

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Amber force field for phenix.real_space_refinement?
by Sebastian Eustermann 24 Jan '18

24 Jan '18

Dear All, I just wondered whether/how one can use the Amber force field also for phenix.real_space_refinement? I tried “use_amber=True” as it is implemented for phenix.refine but that option does exists for phenix.real_space_refinement … Thanks for your help BW Sebastian -------------------------------------- Sebastian Eustermann, PhD Gene Center LMU Munich, Germany

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phenix.auto_sharpen expected filtration of input map
by Ricardo Righetto 24 Jan '18

24 Jan '18

Hi, So far I have liked very much the results of phenix.auto_sharpen, but one thing is not yet clear to me: how does it expect the input map to be filtered? Would be something like: a) Unsharpened, unfiltered map (e.g. the simple average of the half-maps) b) Unsharpened, SSNR-weighted (Cref) (Rosenthal & Henderson, JMB 2003) c) Doesn't matter / other? Thanks in advance! Best wishes, -- Ricardo Diogo Righetto

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Error with Phenix refine after adding ligand
by Mian-Chee Gor 23 Jan '18

23 Jan '18

Hello all, I run into this problem when I tried to refine my protein structure after adding ligand. The ligand that I am adding is a malonate, and the 3-letter chemical code is MLI. I add the ligand using Coot and it fit perfectly into the electron density map. I then tried to run phenix.refine by giving the protein structure pdb file, the original mtz file and the protein sequence fasta file. However, there was an error message saying missing restraints for the ligand. So I generate the CIF file for the ligand using the Ready Set icon in the toolbar. The ligand CIF file and a updated protein structure pdb file was generated and automatically added to the refinement windows. However, when I run the refinement, I saw this error message: Number of nonbonded interaction distances <0.001:2. Please inspect the output above (or in the log window) and correct the input model file. When I inspect the log window, the error is due to the oxygen atoms in the ligand being too close to each other. Why is there an error if the ligand was generated automatically in Phenix? Has anyone encounter this problem before? How do you solve that? Many thanks in advance! -- Dr Mian-Chee Gor Research Fellow Griffith Institute for Drug Discovery (GRIDD) Don Young Road, Nathan, QLD 4111 Mobile: +61 4 2084 7785 Email: m.gor(a)griffith.edu.au

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Neutron diffraction protein refinement with Phenix
by Rex Palmer 22 Jan '18

22 Jan '18

I would like to contact someone based in or near London whois familiar with Phenix refinement of neutron diffraction protein structures and interpretation of the results. Rex Palmer http://www.bbk.ac.uk/biology/our-staff/emeritus-staff http://www.springer.com/978-1-4641-3954-7

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secondary structure presentation in VMD
by CPMAS Chen 22 Jan '18

22 Jan '18

Hi, Phenix users, This may be a little off-topic. I have posted this in VMD users mail list. I want to try here too to see if anyone experienced similar issue. VMD and pymol gave different presentation on the secondary structure of a protein. During phenix.refinement, I added secondary structure restraints and correctly labelled all helices and sheets. However, VMD does not correctly present the secondary structure in cartoon/new-cartoon presentation. A little more detail. In VMD-1.9.4a12, after I loaded the pdb, I chose new cartoon to present the secondary structure. All chains are presented as random coil, the same as tube representation. However, pymol correctly shows the secondary structure of the same pdb file in cartoon representation. Has anyone encountered similar situation? what would be the fix? Thanks! Best Regards, Charles -- *************************************************** Charles Chen Research Instructor University of Pittsburgh School of Medicine Department of Anesthesiology ******************************************************

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Refining a neutron structure
by Rex Palmer 19 Jan '18

19 Jan '18

When refining a neutron structure with Phenix why would the program appear to think it was an X-ray structure? Rex Palmer http://www.bbk.ac.uk/biology/our-staff/emeritus-staff http://www.springer.com/978-1-4641-3954-7

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XChem compound design: recruiting programmer / software engineer
by Frank von Delft 19 Jan '18

19 Jan '18

Dear MXers We are recruiting a software engineer (or scientific programmer, or geek-minded scientist, or scientifically-minded geek) to help us get a lot better at designing compounds from hits from crystallographic fragment screening. The post is linked to the XChem facility <http://www.diamond.ac.uk/Beamlines/Mx/Fragment-Screening.html> at Diamond's beamline I04-1, set up in partnership with the SGC-Oxford, which is now routinely hosting users every week, allowing them to find convincing fragment hits with a few days' worth of experiments. In 2017, over 30 users measured over 35,000 crystals in academic and industrial XChem experiments. To confront the next bottleneck, namely converting low potency fragments into high-potency compounds, we are setting up a suite of easily accessible computational tools that streamline the obvious yet surprisingly fiddly analyses by which to identify the most sensible follow-up compounds that are easy to make or procure. The (initially) two-year post will, in a team of three and depending on interests, build infrastructure, harden existing algorithms or help evolve new ones, do web interface design, or any combination of the above. The project is seeding a nascent effort, for now aspirationally code-named CCP-CMC (/CompMedChem/, http://www.ccp-cmc.org/), to bring the awesome collaborative ethos of CCP4 and other MX tools to computational medicinal chemistry. Recruitment details are here <https://www.recruit.ox.ac.uk/pls/hrisliverecruit/erq_jobspec_version_4.disp…>. Deadline is Monday 29 Jan (it's wrong in the link). -- Prof Frank von Delft Principal Beamline Scientist: I04-1 Diamond Light Source +44 1235 778997 (office: M,T,T) +44 7471 026103 (mobile) Principal Investigator: Protein Crystallography Structural Genomics Consortium Oxford University +44 1865 617583 (office: W,F)

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Calculate F/sigma(F)
by Cygler, Miroslaw 19 Jan '18

19 Jan '18

Hi, I would like to calculate distribution of F/sigma(F) as a function of resolution for reflections in an mtz file. Is it possible to do it Phenix? Thanks, Mirek

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Re: [phenixbb] Fourier_shell_correlation_(FSC)_in_cryo-EM_refinement
by Takanori Nakane 19 Jan '18

19 Jan '18

Hi Oleg, Do you mean FSC between a model and a map? You can calculate it with phenix.model_vs_map. Best regards, Takanori Nakane > I started to do some refinements of cryo-EM structures. But I could not > find FSC (e.g. FSC average) quality metrics in the refinement log. Is it > because of the real space refinement methodology or some features need to > be activated? Please advise > Thanks > Oleg ? > _______________________________________________ > phenixbb mailing list > phenixbb(a)phenix-online.org > http://phenix-online.org/mailman/listinfo/phenixbb > Unsubscribe: phenixbb-leave(a)phenix-online.org

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Local sharpening error
by Ricardo Righetto 19 Jan '18

19 Jan '18

Hi, I am trying to do local sharpening with phenix.auto_sharpen, with the following command: phenix.auto_sharpen map.mrc resolution=4.0 local_sharpening=True Then it runs the global sharpening first as expected, but when it gets to the local sharpening it crashes with the following error: Sorry: Please specify a sequence file with seq_file=myseq.seq Nowhere it says that I would need a .seq file in order to do local sharpening (global sharpening works fine). Any ideas? Thanks, -- Ricardo Diogo Righetto

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Autobuild in to "extra density"
by Tom Terwilliger 18 Jan '18

18 Jan '18

Hi Ben, I think you've done the hard part already by building a poly-ala model into your extra density! If you want to try and sequence it using the density, you can use phenix.replace_side_chains with the keyword "sequence_from_density=True" to do this. See: https://www.phenix-online.org/documentation/ reference/replace_side_chains.html To use autobuild with this, add an extra line to your sequence file with the sequence of the extra piece (separate it from the previous sequence with a blank line or a ">".) I would try rebuild_in_place=True to try and optimize the position of your extra chain. You can specify what residues to work on with something like: rebuild_chain_list=A rebuild_res_start_list=27 rebuild_res_end_list=35 This will rebuild chain A27 through A35. For density modification you might want to use a mask based on your model. For this you would say: mask_from_pdb=my_existing_pdb_file.pdb Let me know if that doesn't do it! All the best, Tom T Date: Tue, 9 Jan 2018 20:50:41 +0000 From: "Flath, Ben" <bef206(a)mail.usask.ca> To: "phenixbb(a)phenix-online.org" <phenixbb(a)phenix-online.org> Subject: [phenixbb] Autobuild in to "extra density" Message-ID: <52cba352941e48869fc9d5223a97ccaf(a)Mail06.usask.ca> Content-Type: text/plain; charset="us-ascii" Hi All I have a structure I am building/refining at 2.6 A resolution, there are three NSC molecules in P321 unit cell. Each monomer contains 150 aa and are at least 95% built. Here is where I need some help. There is extra density. Gel and Mass Spec data suggests that there is a smaller MW weight protein/band contained in the crystals which is most likely a fragment of my target protein. Basically I have 3 NCS copies plus a half a molecule that does not appear to have the same tertiary structure (LSQ & SSM do not align well) as the other 3 molecules. I have been able to build several poly-A helices in to this density and R/Rfree are now 0.25/0.31. My Question is, how do I set up a phenix run (presumably autobuild) So that I can begin to dock my sequence in to these chains and have them extended? Does my sequence input file need to include more than one sequence string? Asking autobuild to find and build 4 NCS groups does not seem to build anything in to this extra density (Also the sigma level for the extra density chains seems to be somewhat less than the well-defined part) I am guessing this is a rebuild_in_place=false job? Can I specify only a certain chain only to be rebuilt? Also are there some special considerations with regard to density modification I should be aware of? Any help would be much appreciated. Regards Benjamin Flath, M.Sc. Research Assistant, Cygler Lab University of Saskatchewan Department of Biochemistry Room 3D40 HSCI Box 27, 107 Wiggins Road Saskatoon, SK S7N 5E5 Phone: 306 220-7355 email: benjamin.f(a)usask.ca<mailto:[email protected]> -- 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: 505-431-0033

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Fourier shell correlation (FSC) in cryo-EM refinement
by oleg＠quantumbioinc.com 18 Jan '18

18 Jan '18

I started to do some refinements of cryo-EM structures. But I could not find FSC (e.g. FSC average) quality metrics in the refinement log. Is it because of the real space refinement methodology or some features need to be activated? Please advise Thanks Oleg

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