May 2008 - phenixbb - phenix-online.org

effect of solvent fraction on density modification/solvent flattening for a membrane protein
by Pascal EGEA 08 Jun '08

08 Jun '08

Dear All, This is a question about the effect of solvent fraction estimation on the quality of the initial phases. I am trying to solve the structure of a membrane protein at moderate resolution 3.5A from a MAD data set (peak, inflection and high energies). I have one copy of my complex which gives me a solvent fraction of 0.7 without considering the contribution of the detergent. With a related molecule I found a Phaser-MR solution but it does not refine although it is right. I am using Phenix with the phases obtained from molecular replacement and combining them with the MAD signal to locate the seleniums. A visual inspection of the anomalous fourier difference map shows 6 sites out of the 7 expected at 4sigma contouring. If I let Phenix decide by itself it goes on its own with two copies in the ASU and considers a solvent fraction of 0.50; then it finds 7 sites (and not 14 ? why is that?) (the seventh is weak but we expect this for this region of the complex). now if I force Phenix to take ncs_copies=1 and solvent fraction=0.7 then it only find 6 sites. Wether it is 2 "freely chosen" molecules/ASU and 0.5 of solvent or 1 "forced" molecule/ASU and 0.7 of solvent, the 6 first sites are identical (although occupancies are quite higher in the first case) Should I take into account the detergent and lower somewhat my solvent fraction (in the 0.6 range maybe) with the fixed one copy ASU estimation or just trust Solve/Resolve when it runs the density modification part. Does it really affect the quality of the phasing? Between these two extremes I am surprised to see that the quality of the resolve map are quite similar apparently showing clear new structural features. Thanks in advance for your comments, Pascal F. Egea, PhD Post Doctoral Researcher University of California San Francisco Department of Biophysics and Biochemistry Robert Stroud Laboratory pascal(a)msg.ucsf.edu

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phenix.elbow
by Morten Grøftehauge 03 Jun '08

03 Jun '08

Dear Phenix.BB, I wrote a mail earlier about some problems I had with phenix.elbow but it didn't seem to get through. I've solved two of the problems now but also found a new one so I'll try posting again. When you set the --xyz option along with --clean then your .xyz file is deleted. Of course the easy solution is simply to not use --clean but I imagine that it is a minor bug since it doesn't happen with --tripos. Secondly I have a slightly larger problem. When an isoSMILES with more than one molecule is inputted then phenix.elbow joins them up to a single molecule (or places them so closely that all programs, including phenix.elbow, interprets them as one molecule when converting to a format such as mol2 with explicit bonds). For an example try phenix.elbow --output=009_3085017 --write_hydrogens=false --overwrite --clean --tripos --smiles='C=CCN.C1C(O1)CCl' The period is supposed to designate two seperate molecules. Remember to use elbow.become_expert before running that line. I hope someone can help me. Sincerely, -- Morten K Grøftehauge PhD student Department of Molecular Biology Gustav Wieds Vej 10 C 8000 Aarhus C - Denmark Phone: +45 89 42 52 61 Fax: +45 86 12 31 78 www.bioxray.dk

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shell variable SSH_Path not set
by shivesh kumar 03 Jun '08

03 Jun '08

Dear all, We have installed Phenix in Red Hat Linux enterprises 5. It takes a long time for the GUI to appear with the following message-- Shell variable SSH_Path not set What is the solution of this problem. Thanx in advance for suggestions. shivesh

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Error running cci_apps
by JENDREK 30 May '08

30 May '08

Hi, I've encountered following error running cci_apps (25.05.08 build): Sorry: Error reading CIF file: "/usr/local/cci_apps/cci_apps_sources/mmtbx/mmtbx/monomer_library/mod_rnaC2.cif" (IOError: [Errno 2] No such file or directory: '/usr/local/cci_apps/cci_apps_sources/mmtbx/mmtbx/monomer_library/mod_rnaC2.cif') I thought it might be my data fault but the same error appears during test_apps script. I'm running cci_apps on the Mac (Tiger 10.4.11). Funny thing that Phenix 1.3rc2 is running without the problem. I hope someone can help me solve the mystery... Andrzej -- alnyds[at]gmail[dot]com

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prosthetic group
by Bryan W. Lepore 30 May '08

30 May '08

should prosthetic groups be attached to proteins by those LINK or CONNECT records as found in typical PDB files? e-LBOW seems for _ligands_ only. -bryan

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BEAM TIME AVAILABLE FOR MACROMOLECULAR CRYSTALLOGRAPHY
by Cyndi Salbego 29 May '08

29 May '08

BEAM TIME AVAILABLE FOR MACROMOLECULAR CRYSTALLOGRAPHY AT THE TWO ID BEAMLINES OF NE-CAT AT APS. Beamline 24ID-C: Variable energy between 6-18keV, ADSC Q315 Detector, MAD Capable. Focused beam size 20x80micron Beamline 24ID-E: Equipped with MD2 microdiffractometer, delivering beam as small as 5 microns. Single energy (12662eV), ADSC Q315 Detector. Contact csalbego(a)anl.gov for further details. See http://necat.chem.cornell.edu for information on our beamlines and a calendar of available days.

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syntax and alternate conformations
by Mark Collins 29 May '08

29 May '08

Hi I have an unexpected result, my syntax must be incorrect. The relevant script commands are below, the problem is residues A113 and B143 have alternate conformation occupancies that sums to 0.98 to 1.06 respectively. Clearly alternate conformations of a single residue should sum to 1 (or less than 1 possibly). Any suggestions please? Thank you, Mark refine { strategy = *individual_sites \ rigid_body \ *individual_adp \ group_adp \ tls \ individual_occupancies \ *group_occupancies \ group_anomalous \ occupancies { individual = None group = chain A and resid 113 and altid A group = chain A and resid 113 and altid B group = chain B and resid 143 and altid A group = chain B and resid 143 and altid B } }

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Re: [phenixbb] problem with high Rfree
by Christina Bourne 28 May '08

28 May '08

Thank you very much for your help. I just wanted to follow up in how I'm progressing with this. I tried the things you suggested, as well as a variety of others, with no luck. It turns out that my 4mol/AU P41 twinned data is ACTUALLY 8mol/AU P212121. The packing in the AU has an almost 41 screw relating 4 mols to the other 4. When this operation is carried out, 2 mols overlay 2 others almost perfect, while the other 2 overlay the other 2 by 180 degrees. So my AU packing is a pseudo-41 with apparent twinning. (The b dimension did not need halving, so my cell is 2x the size, if that makes sense). The data refines very well as P212121, and Rfree drops like a rock. Again, thank you so much for your suggestions, and Phenix is really wonderful! Christina ----- Original Message ---- From: Pavel Afonine <pafonine(a)lbl.gov> To: PHENIX user mailing list <phenixbb(a)phenix-online.org> Sent: Tuesday, May 20, 2008 1:51:42 AM Subject: Re: [phenixbb] problem with high Rfree Hi Christina, I usually observe similar R/Rfree behavior when I use LS target instead of maximum-likelihood. In fact, twin refinement in phenix.refine is based on LS target function. This is just to share my observations; it's not necessarily happening in your case. - How many of test reflections you have and how they are distributed in resolution bins? - Just out of curiosity: did you try to ignore twinning and run refinement with default target? - What if you don't run SA? - Did you try to play with target weights (try different values for wxc_scale and wxu_scale) to see how this affect the R-factors? - Are you using the latest (or one of) phenix.refine? - Did you try to fill in water? Could you send a log file: may be we could spot something outstanding... Pavel. On 5/19/2008 1:32 PM, Christina Bourne wrote: Hello BB, I am working on a structure that is twinned (merohedral) in P41. Initial estimates of twinning fraction (via xtriage and Yeates server) are around 0.37; in refinement they start around 0.49 and drop to 0.46 (so far). My MR soln is good (Phaser LLG ~550) with 4 mols per AU; this gives good packing with no room for another mol. I have data from 48-2.8A. I should mention that data processing wasn't easy- this crystal form also has an apparent epitaxial twin in the b dimension causing a doubling in that dimension. During indexing (with SAINT) I applied a transformation of 100 00.50 001 to the reflections, which then gave me the expected cell and from Xprep the data looks OK. (Yes, I am trying to grow different forms) Maps look nice, although I wish my ligand had more/better density. I ran phenix.refine with defaults, and included twin_law="h,-k,-l", xray_data.r_free_flags.generate=true, detwin.map_types.aniso_correct=true and also simulated_annealing=true. My starting R/ Rfree is 0.448/ 0.4385; ending is 0.2962/ 0.4270. Geometry is somewhat tighter after refinement but is better (bonds 0.017 to 0.01, angles 1.966 to 1.530). I have not included my ligand, and I can see a few spots where the model needs adjusting, but nothing majorly wrong. Why is my Rfree hanging so high? Is it becaues I have bad karma? Is it to do with the twinning? I am pretty sure my space group is right (based on the above info and the maps look fine; Phaser could not find a solution in P43). There isn't room for anything else in the cell. Any opinions or suggestions are most welcome as I wait for better xtals to grow... Thanks in advance, Christina ________________________________ _______________________________________________ phenixbb mailing list phenixbb(a)phenix-online.org http://www.phenix-online.org/mailman/listinfo/phenixbb

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OXT
by Rife, Christopher L 24 May '08

24 May '08

Should phenix.refine be able to handle OXT? I find it is moving the OXT atom ~2A from where it should be. Do I need to rename it or add a separate definition to the refinement? Thanks, Chris

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IUCr Crystallographic Computing School 2008
by Ralf W. Grosse-Kunstleve 24 May '08

24 May '08

IUCr Crystallographic Computing School 2008 * Sharing our knowledge * Kyoto, Japan, August 18-23 http://www.iucr.org/iucr-top/comm/ccom/kyoto2008/program.html The IUCr Crystallographic Computing School 2008 school aims to bring together both computational methods developers and users interested in looking beyond the interface. The format of the school fosters exchange of ideas via formal lectures, afternoon tutorials, coding challenges and code comparison sessions. The world-wide crystallographic community (including macro- and small-molecule crystallography, powder diffraction, and small-angle scattering) is invited to an intensive session of working together and learning from each other. The schedule of the program is available via the web link above. Abstracts are being added. Thanks to support from sponsors, we have been able to keep the registration cost (including accommodation and meals) below 70,000 YEN (ca. 430 EUR, 665 USD). The number of attendees is limited to 80 students. For more information visit the web site above. The registration deadline is July 25th, 2008. Organizing committee: A. L. Spek (Utrecht University , Netherlands) R. Grosse-Kunstleve (LBNL, USA) M. Yao (Hokkaido University, Japan) A. Nakagawa (Osaka Institute of Protein, Japan) H. Powell (MRC, UK) L. Cranswick (NRC , Canada)

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