- phenixbb - phenix-online.org

How does phenix.fmodel treat isotropic and anisotropic B?
by zhangh1＠umbc.edu 15 Sep '10

15 Sep '10

Hi, I am doing a phenix.fmodel calculation for a PDB structure containing anisotroipc B. If I understand it correctly, the B factor is composed of both the isotropic B for ATOM line (Biso) and the anisotropic B from ANISOU line (Uani): Fc=sigma ( fi * exp (-Biso*s*s) * exp (-st*Uani*s) * exp (i*r*s) ) Please correct me if the above equation is wrong. I also noticed that in PDB, the Uani (after scaling by 10^-4) is generally much smaller than Biso. So I assume that Biso has a much bigger contribution than Uani, the latter only implying the vibrational anisotropicity. However, I did a test calculation by setting all Bio to 0 whereas keeping Uani unchanged. Due to the above assumption, I expected the results should be very different from the native structure; however, coot told me they were just so close... Maybe I am wrong somewhere... Best Regards, Hailiang

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Sep 15, 2010 deadline- User proposal submission for Collaborative Crystallography at BCSB
by Banumathi Sankaran 14 Sep '10

14 Sep '10

Dear Users, The deadline for Nov/Dec 2010 Collaborative Crystallography proposals will be *Sep 15, 2010. * ---------------------------------------------------------------------------------------- Through the Collaborative Crystallography Program (CC) at the Advanced Light Source (ALS), scientists can send protein crystals to Berkeley Center for Structural Biology (BCSB) staff researchers for data collection and analysis. The CC Program can provide a number of benefits to researchers: * Obtain high quality data and analysis through collaborating with expert beamline researchers; * Rapid turn around on projects; and * Reduced travel costs. To apply, please submit a proposal through the ALS General User proposal review process for beamtime allocation. Proposals are reviewed and ranked by the Proposal Study Panel, and beamtime is allocated accordingly. BCSB staff schedule the CC projects on Beamlines 5.0.1 and 5.0.2 to fit into the available resources. Only non-proprietary projects will be accepted. As a condition of participation, BCSB staff researchers who participate in data collection and/or analysis must be appropriately acknowledged - typically being included as authors on publications and in PDB depositions. Please consult the website for additional information at: http://bcsb.als.lbl.gov/wiki/index.php/Collaborative_Crystallography ----------------------------------------------------------------------------------------- How To Apply: To learn more, go to: http://www.als.lbl.gov/als/quickguide/becomealsuser.html To submit a proposal, go to: http://alsusweb.lbl.gov/. Scroll down to "*Structural Biology beamlines (includes protein SAXS)*" and click on "New Proposal." Enter your proposal information, with attention to the following details: * For question 3/First choice, select "5.0.1 (Monochromatic);" for question 3/Second choice, select "5.0.2 (MAD)." * Check box (yes) in response to question (7) "Do you want collaborative crystallography (beamline 5.0.1 or 5.0.2 only) * In question 4, please describe a specific research project with a clear end point. In order to request CC time for Nov/Dec 2010 allocation period, proposals must be submitted by *Sep 15, 2010.* The deadline for CC proposals for the time period Jan/Feb 2010 will be Nov 15, 2010. Regards, Banumathi Sankaran

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Reproducibility of R-factors
by miket＠chem.ucla.edu 14 Sep '10

14 Sep '10

Hi All, I recently used phenix.model_vs_data to evaluate a structure that was refined using Refmac. The R_work and R_free calculated by refmac are 0.18 and 0.20, while model_vs_data calculates them as 0.20 and 0.22. Should I be concerned about this discrepancy? Is it typical for different programs to calculate different values for R-factors using the same data, and if so what is the source of this difference? Seems to me like there shouldn't be much of a difference (at least not 2%). Maybe I'm wrong. Any insight/advice would be appreciated. Thanks, Mike Thompson -- Michael C. Thompson Graduate Student Yeates Lab Biochemistry & Molecular Biology Division Department of Chemistry & Biochemistry University of California, Los Angeles miket(a)chem.ucla.edu

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Deposition of riding H
by Dr. Mark Mayer 14 Sep '10

14 Sep '10

Here's one for the community, which I'll post to both Phenix and CCP4 BBs. Where does the crystallographic community stand on deposition of coordinates with riding hydrogens? Explicit H are required for calculating all atom clash scores with Molprobity, and their use frequently gives better geometry (especially at low resolution). Phenix uses explicit riding H for refinement, and outputs these in the refined PDB. Refmac also uses riding H but does not output H coordinates. While depositing a series of structures refined at 1.4 - 2.75 A with Phenix got the following email from the RCSB, who asked I resupply coordinates without H for two of the structures. Since we can't see H even at 1.4 Å I don't understand why an arbitrary cut off of 1.5 Å was chosen, and also why explicit H atoms used in refinement and geometry validation should be stripped from the file. FROM RCSB We encourage depositors not to use hydrogens in the final PDB file for the low resolution structures (> 1.5 A). Please provide an updated PDB file. We request you to use processed PDB file as a starting point for making any corrections to the coordinates and/or re-refinement. -- Mark

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Re: [phenixbb] Deposition of riding H
by Jeff Headd 14 Sep '10

14 Sep '10

Hi Mark, If hydrogens are used to arrive at a final refined model (whether riding or not) it is essential for the reproducibility of results that the H atom records be included in the deposited model. How B-factors are specified and some final atomic positions (such as rotatable methyl groups) are difficult or impossible to predict once removed, so without their deposition this information would be lost and any published statistics would not be reproducible as published. This point is illustrated in one of our recent papers: Afonine PV, Grosse-Kunstleve RW, Chen VB, Headd JJ, Moriarty NW, Richardson JS, Richardson DC, Urzhumtsev A, Zwart PH, Adams PD: phenix.model_vs_data: a high-level tool for the calculation of crystallographic model and data statistics. J. Appl. Cryst. 2010, 43, 669-67. Further, there is no universal standard currently in use that specifies H bond-lengths (some use electron cloud distances, others neutron distances, some a mixture of both), meaning that without inclusion of H atom records (or at least a reference to which library was used) it is very difficult to know where the H atoms were placed. Thanks, Jeff On Tue, Sep 14, 2010 at 10:32 AM, Dr. Mark Mayer <mayerm(a)mail.nih.gov> wrote: > Here's one for the community, which I'll post to both Phenix and CCP4 BBs. > > Where does the crystallographic community stand on deposition of coordinates > with riding hydrogens? > Explicit H are required for calculating all atom clash scores with > Molprobity, and their use frequently gives better geometry (especially at > low resolution). Phenix uses explicit riding H for refinement, and outputs > these in the refined PDB. Refmac also uses riding H but does not output H > coordinates. > > While depositing a series of structures refined at 1.4 - 2.75 A with Phenix > got the following email from the RCSB, who asked I resupply coordinates > without H for two of the structures. Since we can't see H even at 1.4 Å I > don't understand why an arbitrary cut off of 1.5 Å was chosen, and also why > explicit H atoms used in refinement and geometry validation should be > stripped from the file. > > FROM RCSB > > We encourage depositors not to use hydrogens in the final PDB file for > the low resolution structures (> 1.5 A). Please provide an updated PDB > file. We request you to use processed PDB file as a starting point for > making any corrections to the coordinates and/or re-refinement. > -- > > Mark > _______________________________________________ > phenixbb mailing list > phenixbb(a)phenix-online.org > http://phenix-online.org/mailman/listinfo/phenixbb >

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Re: [phenixbb] autobuild : change reflection file mid-job?
by Thomas C. Terwilliger 14 Sep '10

14 Sep '10

Hi Bryan, Yes, I think to change the reflections file you will have to rerun the job as the reflections are read once in autobuild and propagated from there out. All the best, Tom T >> [it was inevitable..] >> >> if i swap the reflection file mid-job - THAT sounds like catastrophe : >> >> so does autobuild determine the format *only* from the .sca, .mtz affix? >> >> and it looks like reflections are read once at startup, and propagated >> from there out? >> >> -bryan >> _______________________________________________ >> phenixbb mailing list >> phenixbb(a)phenix-online.org >> http://phenix-online.org/mailman/listinfo/phenixbb >>

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autobuild : change reflection file mid-job?
by Lepore, Bryan 14 Sep '10

14 Sep '10

[it was inevitable..] if i swap the reflection file mid-job - THAT sounds like catastrophe : so does autobuild determine the format *only* from the .sca, .mtz affix? and it looks like reflections are read once at startup, and propagated from there out? -bryan

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Palestrant, Deborah is out of the office.
by deborah.palestrant＠novartis.com 14 Sep '10

14 Sep '10

I will be out of the office starting 09/13/2010 and will not return until 09/15/2010. I have limited access to email and will respond to your message when I return.

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Re: [phenixbb] autobuild : change .seq mid-job?
by Thomas C. Terwilliger 13 Sep '10

13 Sep '10

Hi Bryan, I think that you can do this, though I have not tried it. You need to replace two files: 1. your original sequence file wherever it is "/wherever/.../myseq.dat 2 a file with the same name "myseq.dat" or whatever, in the directory AutoBuild_run_1_/TEMP0 I would expect all model-building after that to have the new sequence. (Note that runs that are already going as sub-processes will keep their sequences). Now if this is rebuild_in_place, this would not be a good idea. I am assuming it is rebuild_in_place=False, and so it should work... Let me know how it turns out, -Tom T >> i have a long autobuild job going. i'd like to change the .seq files as >> its going - if i keep residue 1 numbered, could this still be a >> catastrophe? >> >> -bryan >> _______________________________________________ >> phenixbb mailing list >> phenixbb(a)phenix-online.org >> http://phenix-online.org/mailman/listinfo/phenixbb >>

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autobuild : change .seq mid-job?
by Lepore, Bryan 13 Sep '10

13 Sep '10

i have a long autobuild job going. i'd like to change the .seq files as its going - if i keep residue 1 numbered, could this still be a catastrophe? -bryan

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