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DEN refinement under phenix
by Melania Strycharska 02 Mar '12

02 Mar '12

Hi All, I was wondering whether anybody has successfully run the DEN refinement under phenix yet. I am having some problems with my scripts stalling without any error messages. What sort of reference models do people use? The following issues I am not quite clear on: - if I don't have a reference model should I call on my current pdb where the script calls for a reference model? - is it ok to use a single domain as a reference model or is it not enough to get the whole protein refined? - is it possible to use more than one reference model; in a case where I had structures of each domain solved separately? - can a reference model be a different protein or does it have to have the same sequence? Thanks a lot!

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Rfree refuse to come down
by #HEW KAI LI KELLY# 02 Mar '12

02 Mar '12

HI, I have a few questions about a dataset that I am working on currently. So I ran Xtraige and it tells me that other than pseudoNCS, there is no other problems like twinning etc. And then I used autoMR and Phaser from Phenix to run molecular replacement with a the structure of the same protein (but that is with DNA bound). The TFZ is more than 9 after from both the runs. Autobuild managed to build the 4 molecules in my ASU (Rfactor/Rfree = 28/32 for a resolution of 2.4A). But because there are some clashes and outliers in the Ramachandran Plot etc, I started to manually refine them in coot. In addition, there is a loop that is unable to fit into the density, so I chopped about 10 residues off each molecule in the ASU. However, as I started to refine the model from AutoBuild, my Rfree begins to climb. So currently, I am at Rfactor/Rfree=27/36. I don't know if there is anything wrong with I had done. So many thanks in advance for your advices on this!! Warmest Regards, Kelly Hew Nanyang Technogical University School of Biological Sciences Division of Structural Biology & Biochemistry Address : #07-01, IMCB, 61 Biopolis Drive, Proteos, Singapore 138673 Telephone (O): +65 65869673 Telephone (HP): +65 98713553

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Fwd: Hi Res Model. Maybe its time to Include Hydrogens?
by Yuri 01 Mar '12

01 Mar '12

Sue: I am not sure they are being included... I have the option checked, but the R values and difference maps tell me otherwise Pavel: A bug? That would be consistent with the behavior I observe. Even when I enable refinement with hydrogens individual or riding, i see essentially no difference in maps or Rfree values. -- Yuri Pompeu

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Hi Res Model. Maybe its time to Include Hydrogens?
by Yuri 01 Mar '12

01 Mar '12

Dear users, I am refining a 400 aa protein with data out to 1.16 A (real data). I am almost finished with refinement. I have good geometry, complete model and ligands Rw 0.11 Rf 0.13. Difference maps seem to be asking for more. See attached screen shot.Both maps 2Fo-Fc (non-filled) and Fo-Fc are contoured at 3 sigma. How should I handle this? I have used hydrogens all along (riding). Thanks for your time -- Yuri Pompeu

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phenix.reciprocal_space_arrays question
by Michael Thompson 01 Mar '12

01 Mar '12

Hi All, I have a very simple question about phenix.reciprocal_space_arrays. I apologize if this is obvious, but I could not find any info in the documentation or the bb archives. I just want to make sure that I am actually doing what I think I am doing. If I provide phenix.reciprocal_space_arrays with an .mtz file containing Fobs and a .pdb file for which I would like to calculate Fmodel and PHImodel, will the resulting Fmodel (and Fcalc, Fmask, Fbulk, etc.) be scaled to the Fobs from the input .mtz? Thanks for the help! Mike T. -- Michael C. Thompson Graduate Student Biochemistry & Molecular Biology Division Department of Chemistry & Biochemistry University of California, Los Angeles miket(a)chem.ucla.edu

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BCA/CCP4 Summer School 2012
by Airlie McCoy 01 Mar '12

01 Mar '12

Applications are now open for the BCA/CCP4 Summer School in Protein Crystallography to be held at Diamond (UK) from Tuesday 28th August to Sunday 2nd September 2012. Applications close 1st May 2012. The BCA/CCP4 Protein Crystallography Summer School is intended for students and researchers new to crystallography. Its dual aims are to provide comprehensive training in crystallography and to promote best practise within the British crystallographic community. The lectures cover the gamut of techniques required for a structure solution, from protein expression through to structure validation. Intensively supervised computer tutorials enable students to relate the theory presented in the lectures to practice. Although CCP4 programs will primarily be used in these tutorials, the aim will be to approach crystallographic questions in a software-agnostic manner. There will also be a crystal manipulation and cooling workshop. (Note that the course is scheduled during Diamond synchrotron downtime, so there will not be active data collection at the Diamond beamlines.) For more information on eligibility, cost, and applications see: http://www.diamond.ac.uk/Home/Events/BCA-Summer-School-2012.html Application form: http://www.diamond.ac.uk/Home/Events/BCA-Summer-School-2012/Application-Pag…

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NCS-averaged and superposed maps
by Mullins, Elwood 29 Feb '12

29 Feb '12

Is it possible to both NCS-average and superpose maps? I can do one or the other easily enough from the command line (phenix.ncs_average) and the GUI (Superpose maps). Unfortunately, both programs require the input to be an mtz file but output ccp4-style maps. I don't see a way to do this sequentially. Is there some other method that would allow me to perform both operations? Thanks, Elwood =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Elwood A. Mullins Ph.D. Candidate Department of Chemistry Washington University in St. Louis Campus Box 1134 One Brookings Drive Saint Louis, MO 63130-4899 Email: elwood.mullins(a)wustl.edu Tel: (765) 496-6814 Fax: (765) 494-7897 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

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R-free flags
by 刘世恒 29 Feb '12

29 Feb '12

Hi, According to the phenix documentation, phenix.refine generates free R that are evenly distributed over the resolution, making sure that relatively thin resolution bins receive enough of reflections. The default behavior is to flag 5% of reflections up to a maximum of 2000. However,in some high-resolution structure, the percent for R-free test set which was generated by phenix.refine might be smaller than 1%， and it was a small percentage. Are there anticles related to the generation of R-free flag by phenix? Sincerely yours, Shiheng Liu

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adding solvents other than water
by Subhani Bandara 28 Feb '12

28 Feb '12

Hi all, How can I identify atoms like Na+, K+ in the map, from the positive density. Also can I add solvents like MPD and Tris buffer if any. Is there a specific way or do I have to run ligand fit. Is there any material I can read on this. Thanks in advance. Subhani

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Fixing ligand position in refine
by Christopher Wanty 27 Feb '12

27 Feb '12

Hi, I have a problem with a phosphate moving out of position during refinement. The complication is that there is an existing phosphate in the same location as the one I'm trying to place, but the existing one is part of a modified residue, and there is clearly density for the alternative conformation of the phosphate, but it is also clearly not still bound to the residue. How do I make sure that the phosphate does not move away from where it should be? Attached image show the phosphate more or less where I want it, and you should be able to see where the existing phosphate is attached to the residue. The large red density blob is where phenix.refine tried to put the phosphate last time. Kind regards, Chris ------------------------------------------------------- Dr. Christopher Wanty christopher.wanty(a)uwa.edu.au Research Associate Biomolecular, Biomedical and Chemical Sciences, Building M310 University of Western Australia 35 Stirling Highway Crawley 6009 Western Australia Australia

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