- phenixbb - phenix-online.org

ligand refinement - elbow
by Christine Gee 01 Mar '08

01 Mar '08

Hi Its taken me a while to get around to it, but I just ran elbow to create a cif file etc for my inhibitor, but the bond lengths are quite different from what I got from the PRODRUG server, and it seems that the pdb file I got out of elbow has a few problems (COOT doesn't join up the aromatic ring for example because the carbons are now too far away on one part of the ring). I was wondering how the bond lengths are selected? It seems it is giving the aromatic carbons a bond length of 1.5, when my previous file (and phenylalanine for example have 1.3). Also, I still am not 100% sure how to add the CONNECT information to make the ligand able to covalently bind to the protein. Regards Christine

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refinement problems
by Christine Gee 01 Mar '08

01 Mar '08

Hi This is a more general crystallography question maybe. I am using phenix.refine and I have a model structure refined against data at 3.4A. The model was built from experimental phasing. I reprocessed the same dataset, to include another angstrom resolution (3.3). It has 50% of the data from 3.4 to 3.3 and the I/sigI is about 2. When I refine my structure at 3.4 the stats are 32 and 36 for R and Rfree, but when I use the phase extended data (and the same reflections are the test set up to 3.4A as long as CCP4i did the job right with setting the Rfree) the stats suddenly jump to 49 and 56 when I refine the model against the higher resolution data. Is there something I am missing? I am doing a rigid and an anneal before individual sites and adp refinement. The space group is P3121. Regards Christine

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input initial TLS parameters
by iulek 25 Feb '08

25 Feb '08

Dear all, I tried to find a way to input initial TLS parameters for the groups into phenix. I know many times this is not advisable, but I wanted to test what comes out from TLSmd server. I could not find any reference on how to do this. Note that I know how to define the groups (a previous question in this bb), the point now is to input initial parameters (origin, T, L, S). Thanks, Jorge

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ligand refinement
by Christine Gee 22 Feb '08

22 Feb '08

Dear Phenix developers I have a covalently bound ligand in my structure and I would like to use phenix to refine the structure. The ligand is bound to the sulfur of a cysteine. What is the best method for defining the ligand. Should I generate a cif file for the whole amino acid and the ligand, or can I make one for just the ligand and add in some restraint somewhere which tells phenix to make a bond between the ligand atom and a nearby sulfur in a cysteine. If I generate a cif file with the whole amino acid and ligand, I assume I will I have to follow some convention in atom naming so that the main chain bonds and angles will form and refine OK? Regards Christine

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Phenix.refine Questions
by Mary Fitzgerald 22 Feb '08

22 Feb '08

First, I have a hopefully easy question. I can't seem to figure it out although feel like I should be able to. Is there a way to run a phenix.refine job in the background? I tried using the & like I usually do and it didn't work. It would be nice to start a job and go home without leaving myself logged into the computer. I didn't see anything in the documentation which makes me think I'm being dull. Second, a technical question. When phenix.refine does ordered solvent, does it use detwinned maps if you've put in the appropriate twin operator and indicated it was twinned? When I've tried running phenix.refine with my perfect twin, it doesn't seem to find waters like I can using the CNS twinned water picking script. Third, is it possible to run phenix.refine in parallel at all. My structure is annoying large and the parallelization of FFT in CNS seems to help speed things up abit. Thanks, Mary X. Fitzgerald Postdoctoral Associate Arnold Lab

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geometry in phenix.refine
by Jianghai Zhu 22 Feb '08

22 Feb '08

Hi, I recently noticed that the geometry in my structure is much worse than my previous model. Here are some examples. The RMSD results after a refinement by phenix 1.3b. stage angl bond chir dihe plan repu 3_bss: 0.711 0.009 0.059 18.282 0.002 3.917 after switching to cci version 2008_02_08_1610, I tried to do a geometry minimization by setting wxc_scale = 0. The RMSD I got from the previous model is as following. stage angl bond chir dihe plan repu 0 : 1.394 0.124 0.147 20.782 0.004 3.925 and after 6 macro cycles of geometry minimization, stage angl bond chir dihe plan repu 6_bss: 0.622 0.011 0.120 13.143 0.003 3.822 It funny that the RMSD are so different for the same model. What happened? Jianghai +++++++++++++++++++++++++++++++ Jianghai Zhu, Ph.D Immune Disease Institute Department of Pathology Harvard Medical School 200 Longwood Ave., Boston, MA 02115 Ph: 617-278-3211 Fx: 618-278-3232 +++++++++++++++++++++++++++++++

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Re: [phenixbb] Phenix.refine Questions - specifically running Phenix in the background
by Edward Snell 21 Feb '08

21 Feb '08

Re: <quote> Message: 8 Date: Thu, 21 Feb 2008 14:23:24 -0500 From: "Mary Fitzgerald" <mary.x.fitzgerald(a)gmail.com> Subject: [phenixbb] Phenix.refine Questions To: "PHENIX user mailing list" <phenixbb(a)phenix-online.org> Message-ID: <2fc50e280802211123h192c095x9c65f5bd6f1d4a55(a)mail.gmail.com> Content-Type: text/plain; charset="iso-8859-1" First, I have a hopefully easy question. I can't seem to figure it out although feel like I should be able to. Is there a way to run a phenix.refine job in the background? I tried using the & like I usually do and it didn't work. It would be nice to start a job and go home without leaving myself logged into the computer. I didn't see anything in the documentation which makes me think I'm being dull. </quote> Apologies if someone has already answered this but you can set up a little command file e.g. 'refine.com', something along the lines of: phenix.refine model_from_coot.pdb data.mtz ligand.cif my_favourite.params --quiet With all your parameters in 'my_favourite.params' and run it with > nohup ./refine.com & You can then log off and check it later and it will still be running. The key seems to be the nohup and the '--quiet' switch. Works for me, hope it works for you. Cheers, Eddie Edward Snell Ph.D. Assistant Prof. Department of Structural Biology, SUNY Buffalo, Hauptman-Woodward Medical Research Institute 700 Ellicott Street, Buffalo, NY 14203-1102 Phone: (716) 898 8631 Fax: (716) 898 8660 Email: esnell(a)hwi.buffalo.edu Telepathy: 42.2 GHz Heisenberg was probably here!

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refining nucleic acids, formats?
by Green, Todd 20 Feb '08

20 Feb '08

Hello All- I'm trying to refine some RNA and I can't seem to get phenix to read in my pdb file as it seems to not recognize the the nucleic acid as nucleic acid, as opposed to protein. By comparison to another pdb from the rcsb site(3b31) I seem to be following the same convention. Any suggestions on what I am doing wrong? I do have protein in the pdb as well. The protein has a different chain id. I am running phenix-1.24.1b, my next move if I can't figure this out is to upgrade. Do I have the format of the RNA wrong? Here is the error message and below that is an example of the first residue of the rna. Cheers- Todd *********************************** sorry the PDB file xxx.pdb has an incomplete residue (or conformer/residue combination) in conformer '' chain R residue U 1 because this conformer is missing the following main-chain atoms: ['N', 'CA', 'C'] *********************************** ATOM 18243 O5' U R 1 50.409 12.832 14.548 1.00144.33 O ATOM 18244 C5' U R 1 49.763 12.566 15.794 1.00144.88 C ATOM 18245 C4' U R 1 49.745 13.804 16.678 1.00145.19 C ATOM 18246 O4' U R 1 49.036 13.579 17.920 1.00145.17 O ATOM 18247 C1' U R 1 49.400 14.624 18.811 1.00145.36 C ATOM 18248 N1 U R 1 49.443 14.148 20.242 1.00145.47 N ATOM 18249 C2 U R 1 48.886 14.949 21.229 1.00145.51 C ATOM 18250 O2 U R 1 48.347 16.024 21.005 1.00145.55 O ATOM 18251 N3 U R 1 48.976 14.439 22.507 1.00145.32 N ATOM 18252 C4 U R 1 49.555 13.242 22.895 1.00145.27 C ATOM 18253 O4 U R 1 49.558 12.920 24.081 1.00145.43 O ATOM 18254 C5 U R 1 50.118 12.468 21.816 1.00145.29 C ATOM 18255 C6 U R 1 50.045 12.940 20.562 1.00145.32 C ATOM 18256 C2' U R 1 50.735 15.197 18.331 1.00145.42 C ATOM 18257 O2' U R 1 50.561 16.545 17.935 1.00145.28 O ATOM 18258 C3' U R 1 51.102 14.243 17.192 1.00145.51 C ATOM 18259 O3' U R 1 51.827 14.863 16.146 1.00146.05 O

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workshop abstract
by Tom Terwilliger 19 Feb '08

19 Feb '08

Hi Peter he is an abstract for my talk. Thanks! -Tom T Phenix Wizards -- Automation of the Structure Determination Process The PHENIX Wizards allow automation of major steps in the structure determination process. The Wizards carry out decision-making, provide suggestions for the user, and form a flexible environment for investigating alternative strategies for structure determination. New algorithms available in PHENIX include a Iterative-build OMIT procedure for prevention of model bias and ligand identification in electron density maps. The PHENIX AutoBuild Wizard can carry out iterative model-building, density modification and refinement to improve the quality of models at resolutions as low as 3 Å. Electron density maps calculated using an atomic model can be affected by model bias introduced during refinement of the model. We have developed a Iterative-build OMIT procedure that prevents model bias in iterative procedures for model-building and refinement while producing a high-quality electron-density map. The PHENIX LigandFit automated ligand-fitting Wizard can fit flexible ligands into an electron density map. The Wizard can identify unknown ligands by comparing a set of potential ligands to the map and finding the one that fits the density most closely. Thomas C. Terwilliger Mail Stop M888 Los Alamos National Laboratory Los Alamos, NM 87545 Tel: 505-667-0072 email: terwilliger(a)LANL.gov Fax: 505-665-3024 SOLVE web site: http://solve.lanl.gov PHENIX web site: http:www.phenix-online.org ISFI Integrated Center for Structure and Function Innovation web site: http://techcenter.mbi.ucla.edu TB Structural Genomics Consortium web site: http://www.doe-mbi.ucla.edu/TB

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Re: [phenixbb] Clashes problem
by Pavel Afonine 14 Feb '08

14 Feb '08

Hi All, 1) phenix.refine has a standard set of geometry restrains as other refinement programs: bond, angle, planarity, chirality, dihedral, non-bonded. Clash score is not something that is included into refinement as a target and then used directly in refinement. Clash scores may be bad at the beginning of structure refinement and should be good at the end. 2) Using H atoms as a riding model should normally help in fixing clashes, however it's not 100% guaranteed: some clashes may be "locked" so the refinement cannot overcome the barriers even with H atoms. In this case what's Luca Jovine suggesting (see one of the emails in this thread) is an excellent thing to do (to add to his receipt: you may also consider using more than default number of macro-cycles). Running simulated annealing is also helpful (use "simulated_annealing=true" flag for this). 3) Since handling of H atoms in phenix.refine is significantly improved in newer versions, I would warmly recommend to use the latest phenix.refine available (currently from CCI Apps: http://www.phenix-online.org/download/cci_apps/). 4) Also, clashes related concerns may be a result of inoptimal weight between Xray target and restrains. Although one can play with the weight adjusting scales manually by trying different values of "wxc_scale" parameter ("wxu_scale" is analog for b-factors refinement) the new version of phenix.refine has an automatic procedure for finding the best weight (here "the best" means the weight that leads to the lowest Rfree) (Carsten's suggestion). To use this option: % phenix.refine model.pdb data.mtz your_parameters.par optimize_wxc=true Note this this may take a while to run (depending on resolution and structure size) so consider running it overnight. If none of the above helps, I would be *very* interested to look at the data and model myself to 1) help you find the best strategy to overcome this problem, and 2) find and fix problem in phenix.refine (if any). As always, I promise to keep all data confidential. Pavel.

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