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PX Jobs Team Leader, Postdoc, Tech (SGC-Oxford).txt
by Frank von Delft 24 Aug '07

24 Aug '07

My group has several vacancies to fill immediately: a Team Leader for Infrastructure and Methods Development; two postdoc positions; and a technician. This is the Protein Crystallography group of the Structural Genomics Consortium, Oxford. For details, please see respectively: Team Leader: http://www.sgc.ox.ac.uk/jobs/07057.html Postdocs: http://www.sgc.ox.ac.uk/jobs/07058.html Technician: http://www.sgc.ox.ac.uk/jobs/07067.html Feel free to contact me for details. The remit of the Structural Genomics Consortium (SGC) is to solve human proteins of medical relevance and place them in the public domain without restrictions; it is funded by a consortium of public and industrial funders, and has independently operating sites in Oxford and Toronto Universities and Karolinska Institutet (Stockholm). The Oxford site solved nearly 200 such structures in its first three years, and has now entered Phase II, with 4 years of funding till June 2011; it now has an increased emphasis on chemical biology and membrane proteins. The Protein Crystallography group collaborates tightly with the 5 other groups to get their purified proteins crystallized and solved -- five per month, to be precise. As importantly, with all the robotics and toys you'd care for, and access not only to stacks of real, interesting samples but also to heaps of structured data accumulated during Phase I, we're ideally positioned for development and testing of crystallographic methods, which will be the major scientific thrust of the group in this phase. Enthusiastic crystallographers, especially those that really enjoy the nuts and bolts of the technique and mucking around with tricks and toys, both crystallization and algorithms, are encouraged to apply. phx.

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Help making selections
by James Fraser 23 Aug '07

23 Aug '07

I am trying to refine a structure where I want chains C and D refined anisotropically. Chain A refined isotropically and as a TLS group. Chain B refined isotropically and as a (separate) TLS group. Chain S (waters) just refined isotropically. I've tried playing around with selections on the command line and in the .def file. Yet always end up not getting the refinement to run correctly or have phenix.refine throw an "AssertionError". I'm using the latest CCIapps phenix.refine. Can someone help me out. Below are the excerpt from the DEF file and the error message thrown to the screen. Thanks, James --FROM DEF FILE-- refine { strategy = *individual_sites rigid_body *individual_adp group_adp *tls \ individual_occupancies group_occupancies group_anomalous none sites { individual = None rigid_body = None } adp { individual { isotropic = None anisotropic = "chain c or chain d" } group = None one_adp_group_per_residue = True tls = "chain a" tls = "chain b" } occupancies { individual = None group = None one_occupancy_group_per_residue = False } anomalous_s --FROM LOG FILE-- ----------Target weights (before refinement)---------- Traceback (most recent call last): File "/programs/cci_apps_2007_08_18_1856/cci_apps_sources/phenix/phenix/command_line/refine.py", line 5, in ? command_line.run(command_name="phenix.refine", args=sys.argv[1:]) File "/programs/cci_apps_2007_08_18_1856/cci_apps_sources/phenix/phenix/refinement/command_line.py", line 80, in run refine_object.run( File "/programs/cci_apps_2007_08_18_1856/cci_apps_sources/phenix/phenix/refinement/driver.py", line 1244, in run log = log) File "/programs/cci_apps_2007_08_18_1856/cci_apps_sources/phenix/phenix/refinement/strategies.py", line 268, in refinement_machine log = log) File "/programs/cci_apps_2007_08_18_1856/cci_apps_sources/phenix/phenix/refinement/weight_xray_chem.py", line 137, in __init__ compute_gradients = True) File "/programs/cci_apps_2007_08_18_1856/cci_apps_sources/mmtbx/mmtbx/restraints.py", line 126, in energies_adp_aniso xray_structure = xray_structure, File "/programs/cci_apps_2007_08_18_1856/cci_apps_sources/cctbx/cctbx/adp_restraints/__init__.py", line 113, in __init__ self.check_flags(fl_i) File "/programs/cci_apps_2007_08_18_1856/cci_apps_sources/cctbx/cctbx/adp_restraints/__init__.py", line 181, in check_flags assert not fl.use_u_aniso() AssertionError -- James Fraser jamesfraser(a)berkeley.edu Alber Lab 356 Stanley Hall, QB3 UC Berkeley Berkeley, CA 94720 http://ucxray.berkeley.edu/~jfraser/

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Re: [phenixbb] density modification?
by Tom Terwilliger 23 Aug '07

23 Aug '07

Hi John, Yes, you have several choices for density modification in phenix: 1. Use your experimental Fobs and phases as a starting point for the AutoBuild Wizard. After the first cycle, you will have density-modified phases. In this example below model-building is turned off with maps_only=True to make this go quickly: phenix.autobuild my_fobs_exptl_phases.mtz input_seq_file=seq.dat \ maps_only=True \ n_cycle_build_max=1 n_cycle_rebuild_max=0 Your density-modified phases will be in AutoBuild_run_1_/overall_best_denmod_map_coeffs.mtz after this run. 2. You can also use resolve directly in phenix with a command like this phenix.resolve<<EOD hklin my_fobs_exptl_phases.mtz labin FP=FP PHIB=PHIB FOM=FOM HLA=HLA HLB=HLB HLC=HLC HLD=HLD no_build solvent_content 0.45 EOD Either of these will do solvent flattening and histogram matching. If you have ncs you can specify it with a set of matrices or with a set of heavy-atom positions in a PDB file that show the NCS with: ha_file heavy_atoms_with_ncs.pdb All the best, Tom T . 03:26 PM 8/22/2007, you wrote: >Is there a way to do density modification in Phenix (solvent and or >histogram)? If so how? > >Thanks, >John Bruning >_______________________________________________ >phenixbb mailing list >phenixbb(a)phenix-online.org >http://www.phenix-online.org/mailman/listinfo/phenixbb 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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density modification?
by John Bruning 22 Aug '07

22 Aug '07

Is there a way to do density modification in Phenix (solvent and or histogram)? If so how? Thanks, John Bruning

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Re: [phenixbb] Question about antibumping restraints and restraints on dihedrals
by Ralf W. Grosse-Kunstleve 22 Aug '07

22 Aug '07

Hi Madhu, > 1. Is there a way of applying antibumping restraints to decrease the > number of clashes in phenix.refine, I looked at older posts but couldn't > get a satisfactory guideline regarding the same. The antibumping restraints (nonbonded interactions) are on by default. Currently there isn't a syntax to turn them off or to change the default parameterization. If you refine for a few cycles with the weight for the x-ray target set to zero (wxc_scale=0) the clashes should definitely go away. Then go back to normal refinement (wxc_scale=0.5). I'd hope that the clashes don't come back. Otherwise that's what the x-ray data guide the minimization to, even though the restraints are pushing back. > 2. The default setttings for geometry refinement looks like this: > refinement.geometry_restraints.remove { > angles = None > dihedrals = None > chiralities = None > planarities = None > } > Do I have to change "dihedrals=True" This will not work: Sorry: Invalid atom selection: refinement.geometry_restraints.remove.dihedrals="True" (RuntimeError: Syntax error.) You have to specify atom selections to *remove* default restraints. > if I do not want to put restraints on > dihedrals. I was thinking that one puts restraints on psi/phi angles only > by setting "discard_psi_phi = False" because when I set it to > "discard_psi_phi = True", the Ramachandran plot was much better. But I did > not want to do this because then the Ramachandran plot is no more a > validation tool. I just wanted to know if Unknowingly I did that by > setting up "dihedrals = None". No, if you leave the geometry_restraints.remove block untouched you'll get all restraints incl. dihedrals, except for the peptide psi and phi angles, which are controlled by the dedicated parameter you quote. Cheers, Ralf

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Question about antibumping restraints and restraints on dihedrals
by Madhumati Sevvana; Biotechnik 22 Aug '07

22 Aug '07

Hi! I could successfully refine a merohedral twin in phenix.refine but I have a few unanswered questions: 1. Is there a way of applying antibumping restraints to decrease the number of clashes in phenix.refine, I looked at older posts but couldn't get a satisfactory guideline regarding the same. 2. The default setttings for geometry refinement looks like this: refinement.geometry_restraints.remove { angles = None dihedrals = None chiralities = None planarities = None } Do I have to change "dihedrals=True" if I do not want to put restraints on dihedrals. I was thinking that one puts restraints on psi/phi angles only by setting "discard_psi_phi = False" because when I set it to "discard_psi_phi = True", the Ramachandran plot was much better. But I did not want to do this because then the Ramachandran plot is no more a validation tool. I just wanted to know if Unknowingly I did that by setting up "dihedrals = None". Thank you in advance. Regards, Madhu. ------------------------------------------ Madhumati Sevvana, PhD Lehrstuhl fuer Biotechnik Friedrich-Alexander-Universitaet Henkestr. 91, D-91052 Erlangen, Germany Tel: 0049-9131-8523083 Email: msevvana(a)biologie.uni-erlangen.de -------------------------------------------

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Re: [phenixbb] low res structures and Phenix
by Tom Terwilliger 21 Aug '07

21 Aug '07

Hi John, I'll answer the first of your questions... -Tom T >I have a couple of questions regarding low res structures in Phenix >(about 3.5 angstroms res). > >1. Can Phenix do B-factor sharpening for improved maps? If not >what program do people usually use for this? If you are using the AutoSol wizard, you can use the keywords: correct_aniso=True b_overall=20.0 to force correction of any anisotropy in your data and to set the overall B to 20.0. Note that this will affect all the maps produced by the AutoSol wizard. I have not yet found this to improve the quality of the resulting model; if it works for you please let me know! You can also use phenix.xtriage to do this: phenix.xtriage perfect.mtz hklout=output.mtz aniso.action=True aniso.final_b=user_b_iso aniso.b_iso=77 will set the b_iso of perfect.mtz to 77 >2. How can one optimize Ksol and Rprobe (bulk solvent model) in Phenix? > >3. Are there any other suggestions for dealing with low resolution >structures in Phenix? > >Thanks, >John Bruning >_______________________________________________ >phenixbb mailing list >phenixbb(a)phenix-online.org >http://www.phenix-online.org/mailman/listinfo/phenixbb 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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cis peptide and pdb head
by Jianghai Zhu 21 Aug '07

21 Aug '07

Hi, How does phenix.refine treat cis peptide? Will it automatically detect it and restrain it like refmac5? or do I have to input the information somewhere? or generally how does phenix.refine treat the pdb head? I remember that some earlier version manual stated that all the head information are discarded, is that correct? Jianghai +++++++++++++++++++++++++++++++ Jianghai Zhu, Ph.D CBR Institute for Biomedical Research Department of Pathology Harvard Medical School 200 Longwood Ave., Boston, MA 02115 Ph: 617-278-3211 Fx: 618-278-3232 +++++++++++++++++++++++++++++++

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low res structures and Phenix
by John Bruning 21 Aug '07

21 Aug '07

Hi, I have a couple of questions regarding low res structures in Phenix (about 3.5 angstroms res). 1. Can Phenix do B-factor sharpening for improved maps? If not what program do people usually use for this? 2. How can one optimize Ksol and Rprobe (bulk solvent model) in Phenix? 3. Are there any other suggestions for dealing with low resolution structures in Phenix? Thanks, John Bruning

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Re: [phenixbb] autobuild wizard question
by Tom Terwilliger 19 Aug '07

19 Aug '07

Hi Jeff, I'm sorry for the trouble with the AutoBuild Wizard! I was not able to duplicate the problem with my version and putting in a model with 2 chains and trying to do rebuild_in_place of just a few residues, unfortunately. Everything seemed to work as it is supposed to. Can you check a couple things: 1. Make sure you have the latest version of PHENIX (development version) from the website. 2. Make sure that the range of residues you want to rebuild is at least 2 in from each end of the chain (so if the chain is 1-350, you can rebuild 3-6 or 347-348 but not 340-350). 3. If you accidentally give the Wizard a range that is too big, it should give you an error message and stop, but if you fix the range then it should go on. 4. Try running the Wizard from the command line, and specify "verbose=True debug=True" which will help because it gives you a lot of output that may help figure out what is going on. You will need to add also " |tee debug.log" to catch the output from this run. If none of those things help, then if you can send me the AutoBuild_run_xx_.output file from your GUI-version run and the output from running from the command line; that may help me figure out what is going wrong. Thanks! -Tom T Jeff Habel wrote: >Im a new PHENIX user and having trouble with the Autobuild wizard. > >The structure has 2 molecules in the asymmetric >unit and I am trying to build a small portion >(286-297) of both chains. I have tried building >both at the same time and trying just chain A >but always receive the error about needing 2 >amino acids on either end for anchoring the >build. Every time I alter the build range (284 >299 282 301 etc) the error persists. > >Any suggestions would be appreciated. > >Thanks, > >-Jeff 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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