- phenixbb - phenix-online.org

gnomebreakpad error
by shivesh kumar 01 Apr '08

01 Apr '08

Dear all, We are trying to install phenix in Fedora Core 8.While installing it is showing the following error- Gtk-Message: Failed to load module "gnomebreakpad": libgnomebreakpad.so: cannot open shared object file: No such file or directory Please suggest what is wrong or missing. Thanx in advance. Shivesh

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tls definitions
by PhilEvans 01 Apr '08

01 Apr '08

Sorry if this has been answered before, but I've only just joined this BB In phenix.refine, I'm trying to make TLS groups consisting of multiple chains, eg refinement.refine { strategy=individual_sites+tls+individual_adp adp { tls="chain A and chain B and chain Z" tls="chain C and chain D and chain Y" } } but it doesn't work: what should I do? Phil ================== Extract refinement strategy and selections ================= individual_sites = True rigid_body = False individual_adp = True group_adp = False tls = True individual_occupancies = False group_occupancies = False group_anomalous = False size = 1356 n_use = 1356 n_use_u_iso = 1356 n_use_u_aniso = 0 n_grad_site = 0 n_grad_u_iso = 0 n_grad_u_aniso = 0 n_grad_occupancy = 0 n_grad_fp = 0 n_grad_fdp = 0 n_anisotropic_flag = 0 total number of scatterers = 1356 Sorry: Empty selection in adp_tls selection.

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question about refinement in a SAD data set
by Pascal EGEA 31 Mar '08

31 Mar '08

Dear All, I am trying to refine a seleno met structures at 2.2 Ang resolution I used Auto_Sol and Auto_Build and it worked great since it found the 4 semets with occupancies of about 0.85 to 0.95. and most of the model was built. Phenix generated an exptl_fp_phases.mtz with the Rfree flag. so far so good. I have a couple of questions because I am not quite to understand what phenix.refine is doing at this stage? 1- If I refine using the experimental phases mtz file generated by the auto_sol run, the occupancies for the seleniums change quite a bit and they drop to 0.75-0.80 and that does not sound right to me? What am I doing wrong? should I fix occupancies for the seleniums to the values evaluated at the end of the auto_build run (Rfree=27/ Rfac=24?) 2- This experimental phases mtz file contains FP and the HL coefficients for the phases but there are no more anomalous differences. If I try to refine f' and f" using it, Phenix tells me that there is no anomalous information contained in this file. So how do you refine f' and f"? and what is the practical reason for this AutoSol generated mtz file to not contain the anomalous differences that were used to locate the seleniums. Thanks in advance for the explanation 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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Getting Residual Bs
by Frank von Delft 30 Mar '08

30 Mar '08

Hi Pavel, picking up on your point earlier: > and that there are tools available from both ends (phenix, ccp4) to easily > go from partial to total and back. What *is* the tool in phenix to from total to partial? I suspect it's one of the phenix.pdbtools adp commands, but the documentation is a bit sparse on that program. Cheers phx P.S. Pavel, despite my rant today: great program! :-)

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Re: [phenixbb] refmac,tlsanl vs TLS, B and anisou
by Paul Adams 30 Mar '08

30 Mar '08

Some comments: - We (the PHENIX developers) are working with the PDB to come up with a more streamlined deposition of TLS information for PHENIX. There are some other issues that need to be resolved first that have slowed this down a little. - I am in agreement with George (not unusual). - As far as I remember Garib was supportive of the idea of no longer depositing residual B-factors in the atomic iso-B column. - What phenix.refine writes in the PDB file is almost exactly the same as you would get by running TLSANL on a REFMAC PDB file. - It is my understanding that the EBI runs TLSANL on REFMAC deposited PDB files to extract the ANISOU records so that R-factors can be calculated. It would seems that this information is then discarded. [I could be mistaken about this whole process though] - Allowing ANISOU records only when atomic anisotropic displacement parameters have been refined seems very restrictive. There may be multiple ways to arrive at anisotropic displacements other than the traditional method (TLS is one, George mentioned TLS restraints instead of constraints, and we have some ideas about ADP refinement that would also result in anisotropic displacements). - It is good to remember that TLS refinement is constrained anisotropic displacement parameter refinement. - If we want bioinformaticians to analyze our structures then we should be writing something in the iso-B column that they can understand - I favour the iso-B equivalent of the total atomic B-factor. This I assume they can handle. I very much doubt that anyone other than a crystallographer will go to the trouble of extracting the TLS information and recalculating atomic displacements. - The biologists looking at structures from the PDB do not care about TLS or ANISOU records. If they choose to look at anything it will be the iso-B column (probably by colouring the atoms by B-factor in a display program). I'd like to give them a fighting chance of seeing something meaningful such as the iso-B equivalent of the total atomic B-factor rather than a residual B-factor (which has no meaning to them). - I will not be holding my breath waiting for any of the popular display programs to start interpreting TLS header information. - I agree that it is best for everyone if we have some clear standards for deposition and tags that make it clear to anyone looking at files from the PDB what is meant by the contents. The PDB is very aware of this and I expect things to be straightened out fairly soon in collaboration with the developers of phenix.refine and REFMAC. -- Paul Adams Deputy Division Director, Physical Biosciences Division, Lawrence Berkeley Lab Adjunct Professor, Department of Bioengineering, U.C. Berkeley Vice President for Technology, the Joint BioEnergy Institute Head, Berkeley Center for Structural Biology Building 64, Room 248 Tel: 510-486-4225, Fax: 510-486-5909 http://cci.lbl.gov/paul Lawrence Berkeley Laboratory 1 Cyclotron Road BLDG 64R0121 Berkeley, CA 94720, USA. --

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Rant: B vs TLS, anisou, and PDB headers
by Frank von Delft 29 Mar '08

29 Mar '08

Just spent an hour trawling docs, BBs (recent threads) and logs to figure out what the hell my B column is telling me (phenix vs refmac vs pdb). Oh dear, it's a disaster area, quite Heissenbergian... the most important number (uncertainty) is itself unknowable: * Phenix writes total ADP, Refmac writes residual ADP. * Refmac writes a remark -- pdbdep strips it (!?!!?) * Phenix writes no remark (I think?) * Refmac writes different numbers to TLSOUT and pdb header (trace of S) * Phenix duplicates the information in header (TLS) and ANISOU cards, the latter thereby making implicit what should be explicitly stored: how the ADPs are connected. * Refmac, given phenix TLS-originating ANISOUs, flattens them into first number, but does not remove them * PDB does not care I'd like to appeal for an urgent consensus -- which should be unusually easy, since it involves only two programs and one repository. My strong recommendation, from first principles of usability: residual B into ATOM, no TLS in ANISOU, and the rest into the header. I know it's religious, but here's the reasoning: ==> the end-user looks *locally*, that's what ATOM and ANISOU are for. ==> global stuff (cell, symmetry, NCS, and yes, TLS) belongs in the header -- as do what's still missing, namely twinning, lattice modulations, scatter factors, and restraints. Yes, we crystallographers want easy B-factor stats (phenix's reason), but then lets fix the analysis programs to look at the header as well. And yes, packing and internal motions (TLS) are all very important for analysis - but that is why it should be explicit in the header, so that graphics tools have easy access to it. End rant (but not end hope :) phx.

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error when optimize_wxc w/o optimize_wxu turned on
by C. Briand, Biochemisches Inst. 28 Mar '08

28 Mar '08

Dear Phenix Users, We are currently using the last version of phenix in our lab. ------------------------------------------------------------------------------- PHENIX: Python-based Hierarchical ENvironment for Integrated Xtallography Version: 2008_02_08_1610 Release tag: rc6 User: briand ------------------------------------------------------------------------------- When we are using phenix.refine to refine a structure and we are turning on optimize_wxc w/o optimize_wxu, the job failed. Any ideas ? Many thanks Christophe =============================================== Dr. Christophe Briand Biochemisches Institut Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland http://www.bioc.uzh.ch/gruetter/ ===============================================

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sugar links
by Alessandro Nascimento 27 Mar '08

27 Mar '08

Hi all, I'm trying to apply a cif link modification for MAN-MAN link and found this post explaining how to do that: http://www.phenix-online.org/pipermail/phenixbb/2007-July/000332.html However the syntax refinement.pdb_interpretation.apply_cif_link { data_link = NAG-NAG-b-D residue_selection_1 = chain A and resname NAG and resid 901 residue_selection_2 = chain A and resname ASN and resid 900 } gives me the following error *** apply_cif_link: data_link: NAG-NAG-b-D Sorry: Missing CIF link: data_link_NAG-NAG-b-D Please check for spelling errors or specify the file name with the link as an additional argument. *** Has the syntax changed or am I missing something? thanks a lot in advance, --alessandro phenix.refine --version: ------------------------------------------------------------------------------- PHENIX: Python-based Hierarchical ENvironment for Integrated Xtallography Version: 2008_02_08_1610 User: Alessandro -------------------------------------------------------------------------------

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large ASU: problem with upper/lower case chain IDs
by Cherepanov, Peter P 26 Mar '08

26 Mar '08

Dear phenix developers, I am new to this list and apologize in advance if the following has been discussed before. Although, I must say, the problem is rather unusual... well, we are trying to refine a structure with 36 protein chains per asu (not much fun, but it is our best crystal form for this protein). The chains are labeled (by phaser) with UPPER and lower case characters. THE TROUBLE IS, phenix.refine confuses upper and lower case chain IDs. Now, although default refinement (no restraint_group definitions) works, it is very important for us to define groups of residues, in particular, for NCS. I tried defining chains using quotes (e.g chain "i"; or chain 'i', or "chain i", etc,etc), which did not help. Phenix chokes on our pdb file also after automatic NCS search (although it finds and defines ncs groups correctly). It is funny, because, the program does discriminate between upper and lower case characters when referring to an element (e.g. it does not accept "element Se" when coordinate file has got "SE" and vice versa). Analogous refinement (and NCS definitions) works great in Refmac; but would like to compare results and also take advantage of simulated annealing in phenix.refine. Is there a quick fix, without tedious relabeling the chains? In principle, we could use upper case characters, followed by digits 0-9 [that works], but this would make the whole process very difficult for a number of reasons; I hope there is way around it, thank you, Peter PS: we are using v1.3b

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ADP high variance
by Daniel Frey 25 Mar '08

25 Mar '08

Hello, I have a good data set to 1.8 A and refined it with the actual version of phenix, including annealing and isotropic bfactors. Checking the B factor variance in coot revealed high differences in about 50% of the residues. Most of them are at the surface, but still there are residues like phenylalanines and valines within the core where the bfactors jump from 25 to 50 from one carbon atom to the other. Changing wu and wxu_scale did not improve the results. A quick check with refmac improved the results, so i guess I am missing the right restraints for phenix. Which parameters should be changed to improve the bfactor variance in phenix? Thanks for your help Daniel Daniel Frey Department of Biochmistry University of Zurich Winterthurerstrass 190 8057 Zurich Switzerland freyd(a)bioc.unizh.ch Tel: +41446355558 www.biochem.uzh.ch/gruetter www.structuralbiology.uzh.ch

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Scientific Writer Position, Berkeley California
by Paul Adams 24 Mar '08

24 Mar '08

= = ======================================================================== PSI Knowledgebase Scientific Writer, Lawrence Berkeley National Laboratory = = ======================================================================== Scientific Writer/Editor Division: Physical Biosciences SUMMARY: We are seeking an intelligent and motivated structural biologist technology specialist to research, document, and communicate new technologies to the scientific community. This project is part of the NIH-funded Protein Structure Initiative (PSI) Knowledgebase. The position will require interactions with other groups in the Knowledgebase, members of the Protein Data Bank, researchers at NIH- funded PSI centers, scientific journals, and the broader biological research community. The successful candidate will work under the direction of the Principal Investigator for this project. Primary duties and responsibilities are promoting new PSI-developed technologies to the broader scientific community, and editing a web portal describing these technologies. NOTE: This is a one year Term appointment with the possibility of renewal under the same terms and conditions, contingent upon continued funding and availability of work. DUTIES: Essential - Primary duties and responsibilities will include regular communication with researchers at the PSI-funded structural genomics centers and other programs. Interaction with other groups in the PSI Knowledgebase, members of the Protein Data Bank, researchers at NIH-funded PSI centers, scientific journals, and the broader biological research community. Collecting information describing technologies from other PSI-funded researchers and by the use of web and bibliographic search tools. Writing text that describes new technologies to the broad scientific community. Maintaining and editing written and graphical material on a web site devoted to technology dissemination. Extensive email and verbal interaction with other researchers. Marginal - Analysis of crystallographic data. QUALIFICATIONS: Essential - BS, MS or equivalent in a scientific discipline, preferably structural biology, biology, or chemistry. Demonstrated experience of scientific research using either computation or instrumentation. Solid interpersonal skills and the ability to work in a team environment are critical. Ability to communicate with a broad range of researchers. Excellent spoken and written English skills are essential. Marginal - Experience with the solution of macromolecular structures using crystallographic or NMR methods. Practical computational analysis of crystallographic data. Familiarity with scripting languages such as Python. To apply: visit http://cjo.lbl.gov/ and search for the keyword PSI or the job number 21575. Please see http://cjo.lbl.gov/app_instr.html for details of how to apply. -- Paul Adams Deputy Division Director, Physical Biosciences Division, Lawrence Berkeley Lab Adjunct Professor, Department of Bioengineering, U.C. Berkeley Vice President for Technology, the Joint BioEnergy Institute Head, Berkeley Center for Structural Biology Building 64, Room 248 Tel: 510-486-4225, Fax: 510-486-5909 http://cci.lbl.gov/paul Lawrence Berkeley Laboratory 1 Cyclotron Road BLDG 64R0121 Berkeley, CA 94720, USA. --

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Beamline Scientist Position, Berkeley California
by Paul Adams 24 Mar '08

24 Mar '08

= = = = = = = ======================================================================== Beamline Biophysicist Scientist/Engineer, Lawrence Berkeley National Laboratory = = = = = = = ======================================================================== Biophysicist Scientist/Engineer Division: Physical Biosciences SUMMARY: As a member of the Berkeley Center for Structural Biology (BCSB), provide technical and scientific support for users at the BCSB beamlines (http://bcsb.lbl.gov) at the Advanced Light Source in Berkeley California. Work with the BCSB group leader and other BCSB scientists and engineers to develop methodology and instrumentation for collecting and analyzing crystallographic data using synchrotron radiation. Participate on projects involving the structure determination of biological molecules and biomolecular complexes. NOTE: This is a one year Term appointment with the possibility of renewal under the same terms and conditions, contingent upon continued funding and availability of work. DUTIES: Essential - Provide support for users regarding data collection, processing, archiving, and analysis. Play a role in coordinating and participating in engineering projects to advance the capabilities of the beamlines, with a focus on robotics systems for sample handling. Participate in the development of instrumentation and methodology for biological crystallography. Participate in the design, implementation, and evaluation of collaborative experiments involving biological crystallography. Collaborate with colleagues both internal and external to the Berkeley Lab. Prepare documentation for beamline staff and users. Prepare scientific data for publication in refereed journals and present findings at seminars and conferences. Required to occasionally work off-hours and weekends to support users. Marginal - Assist with developing research proposals that lead to continued funding in the area of biological crystallography for the BCSB/ALS. QUALIFICATIONS: Essential - Substantial experience working in the area of synchrotron science using complex instrumentation and computer controls. Experience with robotics hardware and control systems. Experience with the collection of experimental data for biological crystallography. Demonstrated ability to conduct independent research and organize results for publication and presentation documented by publication record in either: physics, biology, bioengineering, biophysics, biochemistry or instrumentation fields. Excellent written communication skills along with strong organizational, analytical, and interpersonal skills. Experience in the use of computer programs required for biological crystallography. Ability to work in a team environment and effectively interact with a broad range of colleagues. Marginal – M.S. or Ph.D. in physics, biology, bioengineering, biophysics, or related field. Experience in UNIX computing. To apply: visit http://cjo.lbl.gov/ and search for the keyword BCSB or the job number 21576. Please see http://cjo.lbl.gov/app_instr.html for details of how to apply. -- Paul Adams Deputy Division Director, Physical Biosciences Division, Lawrence Berkeley Lab Adjunct Professor, Department of Bioengineering, U.C. Berkeley Vice President for Technology, the Joint BioEnergy Institute Head, Berkeley Center for Structural Biology Building 64, Room 248 Tel: 510-486-4225, Fax: 510-486-5909 http://cci.lbl.gov/paul Lawrence Berkeley Laboratory 1 Cyclotron Road BLDG 64R0121 Berkeley, CA 94720, USA. --

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Perfect Twins and Ligand Fit or AutoBuild
by Mary Fitzgerald 20 Mar '08

20 Mar '08

I've got a perfect merohedral twin that is refining quite nicely using phenix.refine. In my detwinned FoFc maps, I see density for for a previously diordered region of protein and at least one ligand I soaked in, possibly more. If possible, I'd like to automate the placement of the ligand and build of the diordered region. The data is 3A so it might not work all that well. From looking at LigandFit( I haven't taken a close look at Autobuild yet), I don't see a way to tell the wizard I have twinning. So, can I use Ligand Fit or Autobuild with twinned data? Will the wizards work if I feed it detwinned data and is there a way to get phenix.refine to output the detwinned data other then as map coefficients? Another question/comment. Can I make detwinned 3Fo-2Fc maps? When I tried using the February version of cci_apps, I got an error when I changed the coefficients on my maps in my phenix.def file. Thanks, Mary

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How to use the STIR command in phenix.refine?
by nick＠silvaggi.com 13 Mar '08

13 Mar '08

Hello, I am refining a high-resolution X-ray structure and I would like to gradually increase the resolution from 1.5 to 1.0A, as I used to do in shelxl. I know the STIR command is the way to do this, but I cannot figure out the syntax to use. Currently I am using the following commands: high_resolution = 1.0 low_resolution = None stir = 1.5 When I run phenix.refine (2008_02_08_1610) it echos a line that says "STIR 1.5" before the first macrocycle, but at each stage I see "(resolution: 1.00 - 21.77)." Obviously I am not using the STIR command correctly. Any advice would be greatly appreciated. Thanks in advance. Nick Silvaggi Department of Physiology and Biophysics Boston University School of Medicine 715 Albany St. R-702 Boston, MA 02118

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Beam Time at BCSB beamlines in Berkeley
by Peter Zwart 13 Mar '08

13 Mar '08

============================================================= Synchrotron Beam Time available for Macromolecular Crystallography at Berkeley Center for Structural Biology Beamlines (5.0.1, 5.0.2, 5.0.3, 8.2.1 and 8.2.2). The ALS is now accepting General User applications for May/June ============================================================= The Berkeley Center for Structural Biology (BCSB) operates five beamlines at the Advanced Light Source in Berkeley. Beamlines 5.0.1, 5.0.2 and 5.0.3 are equipped with the Berkeley Automounter system. Beamline 8.2.2. has a Rigaku Actor sample mounter capable of handling Rigaku, unipucks and ALS style pucks. Beamlines 5.0.2, 5.0.3, 8.2.1 and 8.2.2 have large 3x3 Q315 or Q315r CCD detectors. Beamlines 5.0.2, 8.2.1 and 8.2.2. are MAD stations, whereas 5.0.3 and 5.0.1 are fixed energy beamlines at the Se high energy remote, suitable for Se-SAD experiments. The beamlines generate between 1.5x10^11 and 8x10^11 photons per second of flux into a 100 micron collimator at 1.5 mrad divergence. Please visit http://bcsb.lbl.gov/ for more details about the Center and its beamlines. If you'd like to apply for beamtime at these, or any other ALS macromolecular crystallography beamlines, please submit a General User proposal by March 15, 2008 in order to be considered for the May-June schedules. To find out more, click on: http://www-als.lbl.gov/als/quickguide/independinvest.html We invite you to submit a proposal at: http://alsusweb.lbl.gov/4DCGI/WEB_GetForm/PXProposalEntry.shtml/Initialize You can also request access to any open beam time on the five BCSB beamlines by e-mailing our scheduler at SLOrtega(a)lbl.gov. Any industrial or academic group interested in becoming part of the Participating Research Team for beamlines 5.0.1 and 5.0.2 should contact the Head of the BCSB (Paul Adams: PDAdams(a)lbl.gov, 510-486-4225). (Please note that executed user agreements and proprietary fees, if applicable, must be received at least five working days prior to scheduled beam time.) -- Peter Zwart Beamline Scientist Berkeley Center for Structural Biology Lawrence Berkeley National Laboratories 1 Cyclotron road, Berkeley, CA-94720 Cell: +1 510 289 9246 Fax: +1 510 486 5664

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Collaborative Crystallography
by Banumathi Sankaran 12 Mar '08

12 Mar '08

The Berkeley Center for Structural Biology (BCSB) is pleased to announce a new Collaborative Crystallography Pilot Program (CC) at the Advanced Light Source in Berkeley. Through this program, scientists are able to send protein crystals to BCSB staff researchers for data collection and analysis. The CC Pilot Program provides a number of benefits to researchers: * Obtain high quality data and analysis through collaboration with expert beamline researchers; * Rapid turn around on projects; * Reduced travel costs. CC proposals go through the regular ALS General User proposal review process. They are reviewed and ranked by the Proposal Study Panel, and beamtime is allocated accordingly. BCSB staff schedule the projects to fit into the available resources. Please note that only non-proprietary projects are currently being accepted. In keeping with similar programs the BCSB staff researchers who participate in data collection and/or analysis should be appropriately acknowledged as authors on publications and/or PDB depositions. Please consult the website for additional information at: http://bcsb.als.lbl.gov/wiki/index.php/Collaborative_Crystallography How To Apply: To submit a proposal, go to: http://alsusweb.lbl.gov/4DCGI/WEB_GetForm/PXProposalEntry.shtml For question 3 select "Collaborative PX 501/502." For question 9, please describe a specific research project with a clear end point. In order to request CC time for Mai/June, 2008, proposals must be submitted by March 15, 2007. Questions: For comments or questions, feel free to contact Banumathi Sankaran (BSankaran(a)lbl.gov) or Gari Kloss (MKloss(a)lbl.gov)

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refine error when optimize_wxc w/o optimize_wxu turned on
by shi jiahai 11 Mar '08

11 Mar '08

Hi, Dear all, I was using phenix.refine to refine the structure. Once I turned on optimize_wxc w/o optimize_wxu, the job failed with the following message. ----------xray term weight optimization (wxc)---------- Traceback (most recent call last): File "/Application/phenix/phenix-1.3b-rc6/phenix/phenix/command_line/refine.py", line 5, in <module> command_line.run(command_name="phenix.refine", args=sys.argv[1:]) File "/Application/phenix/phenix-1.3b-rc6/phenix/phenix/refinement/command_line.py", line 82, in run call_back_after_monitor_collect=call_back_after_monitor_collect) File "/Application/phenix/phenix-1.3b-rc6/phenix/phenix/refinement/driver.py", line 1143, in run call_back_after_monitor_collect = call_back_after_monitor_collect) File "/Application/phenix/phenix-1.3b-rc6/phenix/phenix/refinement/strategies.py", line 449, in refinement_machine log = log) File "/Application/phenix/phenix-1.3b-rc6/phenix/phenix/refinement/weight_xray_chem.py", line 256, in __init__ self.wxc_optimization() File "/Application/phenix/phenix-1.3b-rc6/phenix/phenix/refinement/weight_xray_chem.py", line 511, in wxc_optimization wxc = self.holder.wxc The phenix I used is the latest version, 1.3b rc6. The platform is intel-linux-2.6 redhat-e4. Python is 2.4.2 Could anyone please tell me what the problem is? Thank you very much! -- Best Regards, Shi Jiahai

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autobuild errro message
by Christine Gee 05 Mar '08

05 Mar '08

Hi I was using phenix.autoMR and when it tried to go on to autobuild the job ended with the following error message AutoBuild Input failed can only concatenate list (not "str") to list There are two molecules in the asymmetric unit. I tried running phenix.autobuild with the output pdb from molecular replacement and got the same message. The file looks OK to me though. Can you tell me what the problem is? Regards Christine

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problem compiling phenix 1.3 beta rc3
by Melody Lin 05 Mar '08

05 Mar '08

Dear all, I have a problem compiling phenix-1.3beta-rc3 on my Mac OSX tiger ppc. I downloaded the tar file under the sbgrid directory and issued command "sudo ./install" to compile it after unzipping. Everything went OK until the last step when the installer is trying to compile phenix components, ands says it will take an hour, but in 2 minutes it reports failure for the compilation. Could anyone suggest what problem this is? Did I download the wrong tar file? Your input is greatly appreciated! Best, Yan

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Question about occupancy refinement of riding hydrogens
by Schubert, Carsten [PRDUS] 04 Mar '08

04 Mar '08

I just noticed that occupancies of riding hydrogens are being refined by default, in fact I am unable to turn this feature off (CCI-APPs from Jan-8). I was just (very naively) wondering what is the rationale behind this? The B-factor refinement for riding hydrogens is already enabled and should take care of this or not? It looks a bit odd to have hydrogens with occupancy 0.9 sitting on a carbon with occupancy 1.0 at 2.0 A resolution. Cheers Carsten

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Enhancement request for map formats
by Schubert, Carsten [PRDUS] 04 Mar '08

04 Mar '08

Hi, I was wondering if it would be possible to have the choice of generating ccp4 maps in phenix.refine. This type seems to be best compromise so far between compatibility and size. The xplor type ascii maps are 10x the size and do not offer any advantage in a homogeneous OS environment. Converting the maps after the fact is one more step I am trying to eliminate. Cheers Carsten

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Possible to rebuild only certain residues in a molecule?
by Francis E Reyes 04 Mar '08

04 Mar '08

All Can the rebuild process be directed to rebuilding specific residues in the molecule? Can this be extended to build multiple models of a given set of residues? Thanks FR --------------------------------------------- Francis Reyes M.Sc. 215 UCB University of Colorado at Boulder gpg --keyserver pgp.mit.edu --recv-keys 67BA8D5D 8AE2 F2F4 90F7 9640 28BC 686F 78FD 6669 67BA 8D5D

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problem with a twinned data set
by Pascal EGEA 02 Mar '08

02 Mar '08

Hi All This a question of general Crystallography and use of Phenix to deal with twinned data. I am having difficulties with a data set. We have data (2.6 ang resolution) that can be scaled and reduced in P222 with a Rmerge of 7%, the systematic absences show a screw axis ( it is P22(1)2). However MR in Phaser failed in this orthorhombic settings when searching for 2 molecules of the complex in the AU. If we reduce and scale the data in P2(1) and look at the diffraction pattern in HKLVIEW there is a /mmm symmetry. In the monoclinic P2(1) setting we can find 4 molecules of the complex (by MR in Phaser) and can refine it with Phenix to a Rfac/Rfree of 28%/34%. 2 molecules have good electron density whereas the two other ones have one of their domain very poorly defined in density. This is looking very suspicious to me and I am wondering if this refined structure is partially wrong? Meanwhile I used phenix.triage on the data processed in P222 and I am confused with the output. ##----------------------------------------------------## ## Twinning Analyses ## ##----------------------------------------------------## Using data between 10.00 to 3.36 Angstrom. Determining possible twin laws. The following twin laws have been found: ------------------------------------------------------------------------ ------- | Type | Axis | R metric (%) | delta (le Page) | delta (Lebedev) | Twin law | ------------------------------------------------------------------------ ------- | PM | 4-fold | 2.851 | 0.000 | 0.013 | - l,k,h | ------------------------------------------------------------------------ ------- M: Merohedral twin law PM: Pseudomerohedral twin law 0 merohedral twin operators found 1 pseudo-merohedral twin operators found In total, 1 twin operator were found --------------------------------------------- Analysing possible twin law : -l,k,h --------------------------------------------- Results of the H-test on acentric data: (Only 50.0% of the strongest twin pairs were used) mean |H| : 0.368 (0.50: untwinned; 0.0: 50% twinned) mean H^2 : 0.194 (0.33: untwinned; 0.0: 50% twinned) Estimation of twin fraction via mean |H|: 0.132 Estimation of twin fraction via cum. dist. of H: 0.115 Britton analyses Extrapolation performed on 0.14 < alpha < 0.495 Estimated twin fraction: 0.127 Correlation: 0.9955 By comparison if I run the detect_twin routine of CNS it tells me that they are no merohedral twin laws for the point group 222 (using the statistical method of Yeates) ? This is confusing me quite a bit. Assuming that the twinning law suggested by Phenix is correct how should I proceed? I have noticed the section concerning refinement using twinned data in Phenix phenix.refine data.hkl model.pdb twin_law="-k,-h,-l" detwin.map_types.aniso_correct=true but It seems I only have a MR solution in P2(1) but not in P222(1) so how can I refine in P222(1) I will greatly appreciate your input, many thanks. Pascal F. Egea, PhD University of California San Francisco Department of Biophysics and Biochemistry Robert Stroud Laboratory pascal(a)msg.ucsf.edu

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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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