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refinement for ligands with alternative conformation
by zhengyi＠msu.edu 22 Mar '11

22 Mar '11

Hello, I am working on the refinement of a structure about 2.8A, which the substrate ligand has an odd conformation. A blob of negative difference density about 4.8 sigma between the one portion of the ligand and the other. If I break down the ligand into two parts, the negative density disappears, however, one part of the ligands does not fit well. We suspect a mixture of conformations. Any suggestions would be appreciated on how to setup refinement for ligands with alternative conformation. Many thanks, Yi Zheng Department of Biochemistry Michigan State University

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Re: [phenixbb] "FOM" or HL coeffs from model?
by Dyda 21 Mar '11

21 Mar '11

Phoebe, >How can I get phenix to spit out not just PhiModel but an estimated FOM or fake HL coefficients (without experimental phases - just based on how badly my model agrees with FOBS)? And I'd like the weights in their own personal mtz column(s), not just precombined in a "weighte d phi" column.< can sigmaa do that for you from Fcalc (vector) and Fo (magnitude)? Fred [32m******************************************************************************* Fred Dyda, Ph.D. Phone:301-402-4496 Laboratory of Molecular Biology Fax: 301-496-0201 DHHS/NIH/NIDDK e-mail:[email protected] Bldg. 5. Room 303 Bethesda, MD 20892-0560 URGENT message e-mail: 2022476710(a)mms.att.net Google maps coords: 39.000597, -77.102102 http://www2.niddk.nih.gov/NIDDKLabs/IntramuralFaculty/DydaFred *******************************************************************************[m

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B factor sharpening in twinned maps
by Mary Ho 21 Mar '11

21 Mar '11

I'm using phenix-1.7-650. When phenix.refine generates the detwinned maps with apply B-factor sharpening on and no value inputed, is the value the program uses for sharpening output anywhere? Thanks, Mary X. Ho Postdoctoral Associate Arnold Lab Rutgers

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changing the project directory
by Charisse Crenshaw 19 Mar '11

19 Mar '11

Hello, I have recently started a project whose folder was located on my desktop. I would like to move that folder off of my desktop as I've heard that having a messy desktop slows down one's computer. I moved the project directory somewhere else, and this resulted in Phenix not being able to find the project (understandably). So I moved it back to its original location and Phenix could then open the project. So, in an X11 shell, I copied the project folder to the new desired location, then changed the output directory in the Phenix main window to that new path. But when I clicked on the project again, the output directory that is indicated changes back to the original path. Now I am looking through the preferences etc for a way to change the path of the project directory within Phenix and I cannot. Can anyone tell me if this is possible and if so, how do I do it? Thanks, Charisse The Salk Institute for Biological Studies

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Refinement Strategy vs. R gap
by Yuri 17 Mar '11

17 Mar '11

Pavel, It seemed like I had to close the GUI window and reopen it for the default (automatic aniso/iso) to take effect. I ran a TLS with 5 groups and ended up with better statistics. Rwork 0.18 Rfree 0.239 -- Yuri Pompeu

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Refinement Strategy vs. R gap
by Yuri 17 Mar '11

17 Mar '11

Hello phenixers, I am refining a liganded structure at 2.1 and I am pretty far into my modeling. Rfree = .265 rwork= .20 My asu has 399 residues one prosthetic group (3178 atoms) and 236 HOH. I just want to do one last refinement round before submission and I am not sure about the strategy I should select as I am running into the following: I- If I refine individuals sites and real space (XYZ) and individual ADP with aniso/iso selection automatic my Rfree goes up slightly and Rwork drops to about .196. I also select optimize x-ray/ADp weight I should say. II- When I choose no XYZ refinement with anisotropic ADP for protein chain only with weight optimization Rwork plummets to 0.15 and Rfree also drops to 0.25. But my gap is now .10 !! I checked my log file and it looks like in default automatic individual ADP phenix.refine is picking all the residues to be anisotropic even though I would not try that at 2.1 A. Could someone point me in the right direction, there is probably something I am overlooking. Thank you -- Yuri Pompeu

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Peptides bonds in cyclic peptides
by Krzysztof Bzymek 16 Mar '11

16 Mar '11

Hi, I've been trying to refine a structure of a protein with a cyclic peptide bound to it. Adding LINK/CONECT to the pdb file works in coot but the bonds are not present after refinement in phenix. I tried creating a param file (I followed recommendations for making ASN/NAG bonds posted here a while ago, but changed the names of connected residues) and included it in refinement, but the bond was not formed and the amino and carboxy groups of respective amino acids were far apart. I also got a message after refinement that a cif file was not specified. What's the solution? Thanks, Chris

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Only one solution in AutoMR with very negative LLG
by Zhang yu 16 Mar '11

16 Mar '11

Hi, I am working on a DNA-protein complex, the protein apo structure is already known. Recently I got a dataset of the DNA-protein complex, I tried to find a solution by autoMR in Phenix with the known protein coordinate as template. I got only one solution with very negative LLG (around -4000), and after rigid body refinement, the both Rwork and Rfree is around 0.55. Was there anyone in the same situation as me? What does that mean if there is just one solution while with very high negative LLG? Thanks

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Need help in refining my twinned P6322(apparent) dataset
by John Pak 15 Mar '11

15 Mar '11

Hey Phenix community, Here are the details of my current situation - any assistance in the matter would be greatly appreciated as I've been struggling mightily for the past month trying to get this structure refined (to no avail). Details: -3.0 angstrom dataset from a membrane protein crystal -reduced in a P3 Bravis lattice using HKL2000 -Pointless and Xtriage suggest P622 symmetry -Solved structure via MR - ran Phaser in all P622 based space groups, found 1 convincing solution in P6322 (LLG ~110) which makes biological sense (1 monomer in ASU that lies on the screw axis to recapitulate the biological trimer) -31% sequence identical search molecule -no pseudotranslation (via Xtriage) Xtriage suggests that the P6322 dataset is nearly perfectly twinned (twin fraction = 0.49). Mindful of the fact that there are no twin operators for P6322, I'm thinking that the true space group is P321, P312 or P63 and I've tried a number of things listed below: 1. Refined in P6322 (simulated annealing+individual B). Missing side chains and incorrectly modelled loops apparent in maps. Start R=0.49, Rfree=0.5. Refinement stalls at R=0.41, Rfree=0.45 after building. 2. Ran Phaser in P312 (using unrefined model) - no solution. 3. Ran Phaser in P321 (using unrefined model). One nice solution (LLG ~220) - lattice looks very similar to P6322 crystal packing. Twin refinement in phenix using operator suggested by Xtriage (simulated annealing + individual B) results in R=0.38, Rfree=0.41 (no rebuilding performed). 4. Ran Phaser in P63 (using unrefined model). Three solutions (LLGs all ~210) - solution #3 looks very similar to P6322 crystal packing. Twin refinement in phenix using operator suggested by Xtriage of solution #3 gives R=0.37, Rfree=0.40 (no rebuilding performed). Solutions #1 and #2 do not give packing arrangements that look like the P6322 solution. Twin refinement of Sol 1 and 2 give higher R factors. So I'm at a loss as to which space group my crystal truly belongs to, and where I should be focusing my refinement. The maps all look similar before and after DM. Thanks for any assistance or recommendations that you might have! -- John E. Pak, Ph.D. Postdoctoral Associate, Stroud Lab Department of Biochemistry& Biophysics UCSF MC2240 Genentech Hall Room S414 600-16th St. San Francisco, CA 94158-2517 Lab #: 415-476-3937 Fax #: 415-476-1902 Cell #: 415-215-0048

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fwd: Re: Need help in refining my twinned P6322(apparent) dataset
by Nathaniel Echols 15 Mar '11

15 Mar '11

---------- Forwarded message ---------- From: "Van Den Berg, Bert" <Lambertus.VandenBerg(a)umassmed.edu> To: "PHENIX user mailing list" <phenixbb(a)phenix-online.org> Date: Tue, 15 Mar 2011 08:01:42 -0400 Subject: Hi John, How do the maps look for cases 3 and 4? Are they great or are there obvious things to correct? Does your model have the correct sequence or is it that of the search model? I’m asking because your R’s seem reasonable to me after a first round of refinement and using a 30% identical search model for MR. So maybe there is no problem? Bert On 3/15/11 2:55 AM, "John Pak" <john.pak(a)msg.ucsf.edu> wrote: Hey Phenix community, Here are the details of my current situation - any assistance in the matter would be greatly appreciated as I've been struggling mightily for the past month trying to get this structure refined (to no avail). Details: -3.0 angstrom dataset from a membrane protein crystal -reduced in a P3 Bravis lattice using HKL2000 -Pointless and Xtriage suggest P622 symmetry -Solved structure via MR - ran Phaser in all P622 based space groups, found 1 convincing solution in P6322 (LLG ~110) which makes biological sense (1 monomer in ASU that lies on the screw axis to recapitulate the biological trimer) -31% sequence identical search molecule -no pseudotranslation (via Xtriage) Xtriage suggests that the P6322 dataset is nearly perfectly twinned (twin fraction = 0.49). Mindful of the fact that there are no twin operators for P6322, I'm thinking that the true space group is P321, P312 or P63 and I've tried a number of things listed below: 1. Refined in P6322 (simulated annealing+individual B). Missing side chains and incorrectly modelled loops apparent in maps. Start R=0.49, Rfree=0.5. Refinement stalls at R=0.41, Rfree=0.45 after building. 2. Ran Phaser in P312 (using unrefined model) - no solution. 3. Ran Phaser in P321 (using unrefined model). One nice solution (LLG ~220) - lattice looks very similar to P6322 crystal packing. Twin refinement in phenix using operator suggested by Xtriage (simulated annealing + individual B) results in R=0.38, Rfree=0.41 (no rebuilding performed). 4. Ran Phaser in P63 (using unrefined model). Three solutions (LLGs all ~210) - solution #3 looks very similar to P6322 crystal packing. Twin refinement in phenix using operator suggested by Xtriage of solution #3 gives R=0.37, Rfree=0.40 (no rebuilding performed). Solutions #1 and #2 do not give packing arrangements that look like the P6322 solution. Twin refinement of Sol 1 and 2 give higher R factors. So I'm at a loss as to which space group my crystal truly belongs to, and where I should be focusing my refinement. The maps all look similar before and after DM. Thanks for any assistance or recommendations that you might have! -- John E. Pak, Ph.D. Postdoctoral Associate, Stroud Lab Department of Biochemistry& Biophysics UCSF MC2240 Genentech Hall Room S414 600-16th St. San Francisco, CA 94158-2517 Lab #: 415-476-3937 Fax #: 415-476-1902 Cell #: 415-215-0048

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