- phenixbb - phenix-online.org

high resolution refinement with phenix.refine
by Pavel Afonine 22 Jan '08

22 Jan '08

Dear phenix.refine users: responding to Vijayalakshmi Janakiraman's questions about refinement at high resolution with phenix.refine, I finally documented this functionality of phenix.refine and supplied it with a small example. This paragraph (see attached HTML file) will be available as part of phenix.refine documentation in the next release of PHENIX and CCI Apps. *Important:* writing this text I assumed that the latest version of phenix.refine is used (currently, it is one from CCI Apps: /2008_01_09_2058/ , http://www.phenix-online.org/download/). Cheers, Pavel. >> I have a high resolution structure with NADP as ligand bound to it. >> I was using CNS to start with. Somehow the Rfree was always very >> high. But when I tried with default options of data= and model=, >> in phenix.refine with the whole data and the intial rigid body >> refined coordinates from CNS, the Rfactors came down to 31%. I have >> now decided to do refinements with phenix.refine. >> Do you suggest any protocol for refinement of structure at this high >> resolution starting from initial rigid body refinements? >> Since I would like to handle alternate conformations in the final >> steps. I am wondering if the 2007 July version could handle >> refinements of alternate conformations. >> Thanks, >> Viji

1 0

Re: [phenixbb] Autosol Feedback and questions
by Tom Terwilliger 22 Jan '08

22 Jan '08

Hi Partha, At 03:53 AM 1/2/2008, you wrote: >Happy new year everybody, > >I had quite a bit of difficulty with a SAD dataset which also showed >Sulphur. Previously I had tried SHELEX to find sites, MLPHARE to >refine, AddSOLVE to find more , and both SOLVE and PHASER to solve >but it did not get to a point where I could do manual building. >Autosol worked beautifully, the input files were scalepack merged >data, ha.pdb (from addsolve step), and the sequence. PHASER to solve >and TEXTAL & RESOLVE with through build option. > >This actually leave me with some confusions / questions: > >1. When I compare the other "solutions", they look like the right >one, just not good enough. Where exactly is the autosol making a >difference? Is it the ability of of TEXTAL to build something more >meaningful when the solution is not good or number of iterations? Autosol uses the quality of the model built as a score, if any model is built (R-factor if < 0.40; number of residues built less 2 * number of chains otherwise).. If no model is built, it uses the standard 4 or 5 criteria that are printed out on the AutoSol wizard screen (CC and R-factor for density modification; skew of electron density histograms, FOM, CC of NCS). >2. How does PHASER know the different anomalous atoms? Does is use a >different scaling factor for SE and S? It can tell by the ratio of anomalous to real scattering corresponding to each atom. >3. I see that phenix.refine has been used in the internal runs, I >have used phenix.refine earlier. But after playing with the side >chains in Coot, when I tried to use the modified pdb file and >resolve.mtz, it complained about the good old Free_R flag. However, >it ran directly in Refmac. Is it a known problem or maybe I did >something stupid? I could do a dry run and change the read mtz and >not cns if that would solve the problem. As Pavel and Ralf have mentioned, this is because AutoSol has tossed a few (usually blank) reflections from your reflection file when it created the refinement file exptl_fobs_phases_freeR_flags_15.mtz # or something similar. Without the "_15" if from AutoBuild The solution is to either (1) use the refinement file from AutoSol (exptl_fobs_phases_freeR_flags_15.mtz), or to delete the MD5 remark record from the AutoSol/AutoBuild PDB file. >4. Lastly, is it possible to use multiple processors to run the job? As Pavel mentioned...we are thinking about this but do not have anything yet. -Tom T 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

1 0

Re: [phenixbb] Continue from an AutoBuild job abruptly killed
by Tom Terwilliger 22 Jan '08

22 Jan '08

Hi Miguel, I'm sorry for the slow response...you can continue AutoBuild by typing: phenix.autobuild run=1 if you were previously on run #1 and you want to continue it. All the best, Tom T At 02:24 AM 1/16/2008, you wrote: >Dear all, > >We had a problem with a machine running >AutoBuild, which resulting in the computer going >down and the AutoBuild job consequently killed. >I've tried to find out if there is a way to >continue the job (it had been running for four >days and still had a few hours to go I guess: a >pretty big unit cell) but I failed. I would >appreciate if someone could point to the >relevant pages in the manual/tutorials or give >me advice about how to do such a thing. If that's possible, of course. > >We're using the latest phenix (1.3b-rc6) and cci apps. > >Thank you! > > >Miguel >-- ><http://www.pangea.org/mol/spip.php?rubrique2>http://www.pangea.org/mol/spip.php?rubrique2 > >~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >Je suis de la mauvaise herbe, >Braves gens, braves gens, >Je pousse en liberté >Dans les jardins mal fréquentés! > >Georges Brassens >_______________________________________________ >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

1 0

Re: [phenixbb] picking Rfree set
by Peter Zwart 22 Jan '08

22 Jan '08

yes, it will. This is useful for when the data is twinned. P 2008/1/22, David Garboczi <dgarboczi(a)niaid.nih.gov>: > So, for instance, when addition of a ligand to a P212121 cell (1 mol) > changes the symmetry to P21 (almost same cell, but 2 mol), the > selection of the Rfree set from the P21 data by phenix.refine will > take the higher almost symmetry into account? > > Dave > > >btw3: the lattice symmetry is taken into account when choosing an free > >set in phenix.refine (unless specified otherwise). If all NCS > >rotational operators are approximately parallel to twin laws, you > >should be fine. > > > >P > > > > > > > > > > > >2008/1/22, Ralf W. Grosse-Kunstleve <rwgk(a)cci.lbl.gov>: > >> > Does phenix.refine take NCS into account when picking the Rfree set? > >> > Thin shells, or other strategy... > >> > >> The short answer is no. > >> We had long internal discussions about this without reaching a final > >> conclusion. In the long run we may integrate alternative R-free set > >> distributions in phenix.refine; in the meantime you have to use > >> an external program (e.g. dataman or sftools). > >> BTW 1: just to prove that we have thought about this subject, we have a > >> simple tool for "visualizing" distributions of R-free flags: > >> iotbx.r_free_flags_accumulation your.mtz > >> It writes a file with x,y pairs which you can plot with e.g. Excel > >> or any other 2D plotting program. > >> BTW 2: The free reflections aren't as free as one may think. When > >> using a maximum likelihood target (any program), the free reflections > >> are used in the estimatation of the error model. This estimation > >> becomes more tricky if the reflections are distributed in thin > >> shells. I.e. if you go to thin shells you may in fact account to some > >> degree for the NCS, but at the same time you compromise the error > >> model estimation. > >> Ralf > >> _______________________________________________ > >> phenixbb mailing list > >> phenixbb(a)phenix-online.org > >> http://www.phenix-online.org/mailman/listinfo/phenixbb > >> > >_______________________________________________ > >phenixbb mailing list > >phenixbb(a)phenix-online.org > >http://www.phenix-online.org/mailman/listinfo/phenixbb > > > -- > David N. Garboczi, PhD > Phone: 301-496-4773 > Investigator, Structural Biology Section (SBS) > Laboratory of Immunogenetics (LIG) > National Institute of Allergy and Infectious Diseases (NIAID) > National Institutes of Health (NIH) > Twinbrook 2/Room 110 > 12441 Parklawn Drive > Rockville, Maryland 20852-1742 > Fax: 301-402-0284 > Email: dgarboczi(a)niaid.nih.gov > > > > > The information in this e-mail and any of its attachments is > confidential and may contain sensitive information. It should not be > used by anyone who is not the original intended recipient. If you have > received this e-mail in error please inform the sender and delete it > from your mailbox or any other storage devices. The National Institute > of Allergy and Infectious Diseases (NIAID) shall not accept liability > for any statement made that are the sender's own and not expressly made > on behalf of the NIAID by one of its representatives. > _______________________________________________ > phenixbb mailing list > phenixbb(a)phenix-online.org > http://www.phenix-online.org/mailman/listinfo/phenixbb >

2 1

picking Rfree set
by David Garboczi 22 Jan '08

22 Jan '08

Does phenix.refine take NCS into account when picking the Rfree set? Thin shells, or other strategy... Dave --

3 3

Re: [phenixbb] autosol : input_ncs_file
by Tom Terwilliger 22 Jan '08

22 Jan '08

Hi Bryan, No, autosol does not let you tell it what the NCS is with input_ncs_file. This is a good idea, however... -Tom T At 06:45 PM 1/15/2008, you wrote: >using PHENIX VERSION: 1.3b of 20-11-2007. > >does phenix.autosol use "input_ncs_file"? > >the documentation implies that phenix.autosol will take `input_ncs_file` >(at the 'find_ncs' entry, "input_ncs_file" is mentioned but no where >else), yet, i get a 'Sorry, unknown file or keyword:' message with no such >command line option listed. > >-bryan >_______________________________________________ >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

1 0

modify_start_model.adp.set_b_iso doesn't seem to work on PDB files with ANISOU cards
by Stephen Graham 21 Jan '08

21 Jan '08

Hi all, I just tried to reset my B values to the wilson B before TLS refinement (in an attampt to shake some model bias that I am sure is hiding somewhere in my temperature factors...). My start model was a TLS-refined PDB file from phenix.refine (hence with ANISOU cards). I issued the following command: > phenix.refine my_model.pdb my_data.mtz modify_start_model.adp.set_b_iso=60 output.prefix=my_model_resetB main.number_of_macro_cycles=0 As far as I can tell, this should reset my B values to 60 and then exit. However, when I look at the resultant PDB file the Bs for all the solvent molecules 60 but for the protein they are not; rather the protein Bs are almost identical to the starting PDB file. If I try to remove the TLS-derived ANISOU cards by adding the command line option "adp.convert_to_isotropic=true" the result is the same (except the output PDB file no longer has ANISOU cards). However, if I strip out the ANISOU cards from my starting pdb file and _then_ run the above command the resultant PDB file _does_ have the correct values for both protein and solvent. It seems like modify_start_model.adp.set_b_iso=60 does not work when atom has an ANISOU card. The behaviour I would *expect* would be for the adp be reset to an 'isotropic' 60 (i.e. set the diagonal elements to 1 and the off-diagonals to 0). Is this a bug, or am I doing something silly? Cheers, Stephen -- Dr Stephen Graham Nuffield Medical Fellow Division of Structural Biology Wellcome Trust Centre for Human Genetics Roosevelt Drive Oxford OX3 7BN United Kingdom Phone: +44 1865 287 549

3 3

d_min_textal=
by Bryan W. Lepore 19 Jan '08

19 Jan '08

the documentation says : "Textal has an optimal high-resolution limit of 2.8 A" is that to say that resolutions != 2.8 are not optimal? -bryan

2 1

Re: [phenixbb] disulfide bonds in phenix.refine
by Ralf W. Grosse-Kunstleve 18 Jan '08

18 Jan '08

Hi Allister, > 1) How do I specifically prevent a disulfide bond from being defined > between two sulfurs that are close together (I tried manipulating the > "disulfide_distance_cutoff" variable but this doesn't seem to stop a > disulfide being formed). If you set, e.g. disulfide_distance_cutoff=0.1 you shouldn't get any disulfide bonds anymore. I just tried it on a small structure and it worked as expected. > 2) How can I soften the restraint on the disulfide bond length for > specific cysteine residues. With the current phenix.refine you cannot edit the automatically determined disulfide bonds (sorry). However, you can use disulfide_distance_cutoff=0.1 to turn off the automatic bonds. Then use geometry_restraints.edits (see documentation at http://phenix-online.org/documentation/refinement.htm) to define the disulfides manually one by one, with the ideal distances and sigmas you want to use. Use a log file from a previous phenix.refine run to obtain the list of all disulfides. Ralf

1 0

disulfide bonds in phenix.refine
by Allister.Crow＠uea.ac.uk 18 Jan '08

18 Jan '08

Hello all, I am currently trying to refine a structure (with phenix.refine) that contains a number of disulfide bonds. Many of these disulfides appear to be partly broken such that the default restraints given to these disulfides by phenix.refine cause the cysteine sulfur atoms to be placed too close to one another. This results in difference density in the fo-fc map. I want to try to model these partially broken states a bit more accurately, either by modelling two alternative conformations (i.e. one cysteine pair in a disulfide and the other pair as free thiols) or by allowing the disulfide bond distance to stretch. Currently refinement drives the S-S bond length close to dictionary values regardless of how far apart I model the cysteines in my input pdb file and whether the density implies a bridge or not. My two questions are: 1) How do I specifically prevent a disulfide bond from being defined between two sulfurs that are close together (I tried manipulating the "disulfide_distance_cutoff" variable but this doesn't seem to stop a disulfide being formed). 2) How can I soften the restraint on the disulfide bond length for specific cysteine residues. Thanks for your time. Dr. Allister Crow

1 0