- phenixbb - phenix-online.org

sharp rise of R-free in resolution bins
by Singh, Bishal 26 Feb '15

26 Feb '15

Hello everyone, I am refining a structure at 2.3 A resolution. R-work/R-free is 26/31 and is not reducing further. When I looked into the resolution bin, I notices a sharp rise of R-free between resolution range 2.5-2.6 A (marked in figure below). However R-work is fine. I am doubtful of reducing the resolution to 2.5 A or lower. Please suggest me your opinion. Your words will be highly appreciated. With regards, Bishal Singh PhD Student University of Heidelberg, Germany

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On Ramachandran restraints of Phenix refine
by Smith Lee 26 Feb '15

26 Feb '15

Dear All, If my resolution was between 2.5-3.0 A, and if I did not use Ramachandran restraints in the Phenix refine the Ramachandran outliers would be increased significantly during the refinement process, in this situation may I use Ramachandran restraints in the Phenix refine? I am looking forward to getting your reply. Smith

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Bug? phenix.hyss crashes on reading CNS def file
by Mark A Saper 24 Feb '15

24 Feb '15

I am trying the example described on this documentation page: http://www.phenix-online.org/download/documentation/cci_apps/hyss/examples.… For mbp.hkl the HySS command suggested is: phenix.hyss $CNS_SOLVE/doc/html/tutorial/data/mbp/mbp.hkl 4 yb —symmetry $CNS_SOLVE/doc/html/tutorial/data/mbp/def The software does not expect the “{“ character in the def file. I can send you the Traceback on request. I am running dev-1951. -Mark

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on TLS for Phenix refine
by Smith Lee 23 Feb '15

23 Feb '15

Dear All, For TLS, the document says, "Can I use both TLS and anisotropic ADPs? Yes, but not for the same atoms - since TLS is essentially constrained anisotropic refinement, the two methods are mutually exclusive". In the "Refinment settings" of the Phenix refine graphical interface, will you please tell me which button is for the anisotropic ADP? The individual B-factors, or the Group B-factors, or only the "Optimize X-ray/ADP weight"? I am looking forward to getting your reply. Smith

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Odd behaviour of real-space refinement
by Tristan Croll 22 Feb '15

22 Feb '15

Hi all, I'm just finalising the re-refinement of a 3.6 Angstrom structure. The stats in general are excellent (Rwork/Rfree = 0.219/0.260; Ramachandran outliers 0.12%; Clashscore < 2; rotamer outliers 2.1%) and I've gone through the whole structure to check and double-check fit to the density. I'm very confident that it's effectively correct. When I run through a fairly standard refinement protocol (XYZ coords, Individual B-factors, optimizing weights, secondary structure restraints), all seems fine - the Rfree rattles around within 0.2% or so. But when I include the real-space refinement option, very strange things start to happen. Each rsrl step causes a 3-4% jump in both Rwork and Rfree, and jumps the Clashscore up to 40 or so. Rotamer outliers briefly go to zero but then increase substantially (to 6+%) in subsequent steps, and the number of Ramachandran outliers increases. I thought I'd missed some dreadful error in my structure until I looked more closely at the results. Some very nonsensical changes have been made - for example, an arginine in the middle of a beta-sheet (admittedly with no observable density associated with its sidechain, but register is well determined by surrounding residues and backbone density is clear) was flipped from its original orientation to point directly into the hydrophobic core of the domain. Somewhat surprising, to say the least. Is this a bug in the algorithm, or is it simply that 3.6A is too low resolution for it to work reliably? My version of Phenix is a nightly build from about 2 weeks ago. Happy to share coordinates and log files if necessary. Thanks, Tristan

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Odd behaviour of real-space refinement
by Tristan Croll 22 Feb '15

22 Feb '15

Hi all, I'm just finalising the re-refinement of a 3.6 Angstrom structure. The stats in general are excellent (Rwork/Rfree = 0.219/0.260; Ramachandran outliers 0.12%; Clashscore < 2) and I've gone through the whole structure to check and double-check fit to the density. The only stat that bugs me a little is the rotamer outliers (2.3%). When I run through a fairly standard refinement protocol (XYZ coords, Individual B-factors, optimizing weights, secondary structure restraints), all seems fine - the Rfree rattles around within 0.2% or so. But when I include the real-space option, very strange things start to happen. Each rsrl step causes a 3-4% jump in both Rwork and Rfree, and jumps the Clashscore up to 40 or so. Rotamer outliers briefly go to zero but then increase substantially in subsequent steps, and the number of Ramachandran outliers increases. I thought I'd missed some dreadful error in my structure until I looked more closely at the results. The attached image is an example of what's happened: an exposed arginine in the middle of a beta-sheet (admittedly with no observable density associated with its sidechain, but register is well fixed by surrounding residues) has been flipped from its original orientation (yellow) to point directly into the hydrophobic core of the domain. Somewhat surprising, to say the least. Is this a bug in the algorithm, or is it simply that 3.6A is too low resolution for it to work reliably? My version of Phenix is a nightly build from about 2 weeks ago. Thanks, Tristan

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Re: [phenixbb] Autobuild iterative omit map error
by Terwilliger, Thomas Charles 21 Feb '15

21 Feb '15

Hi Emily, (Back on-list so others can see the answer.) It seems that your PDB file has a "TER" record between residues ASN 446 and ALA 447 of chain B. Our parsing system interprets that as the end of chain B and thinks that ALA 447 is another chain. You can see this by running: phenix.print_sequence xxxxx.pdb I tried deleting the TER record and it looks as though autobuild will get past the interpretation stage with it taken out. Let me know if that doesn't do it! (Also...do you know why the TER record might be there? It is a little surprising!) All the best, Tom T On Feb 20, 2015, at 9:10 AM, Emilia C. Arturo (Emily) wrote: Thank you Tom! Attached are the reflections file, sequence file, input model pdb file, and the log file from phenix. Emily. On Fri, Feb 20, 2015 at 11:01 AM, Terwilliger, Thomas Charles <terwilliger(a)lanl.gov<mailto:[email protected]>> wrote: Hi Emily, I'm sorry for the trouble! I'll be happy to try and help with it. If you send me (off-list) the input files you are using and the full log file I'll have a look. All the best, Tom T On Feb 20, 2015, at 7:53 AM, Emilia C. Arturo (Emily) wrote: > Hello. > > I'd like to use phenix's Autobuild iterative omit map tool, but have run into an error I could use some help with. When the process aborts, the message that phenix outputs is that the input file has duplicate chains. I looked at the pdb file and I do not see duplicate chains; could the ANISOU records for each atom generated by TLS refinement be hanging up the process? I had no error with Autobuild when I started the iterative map process using an input file that had been generated by phenix.refine using the same configuration as the TLS refinement had used (except, of course, for the TLS parameters). > > Thanks for your attention. > Emily. > > _______________________________________________ > phenixbb mailing list > phenixbb(a)phenix-online.org<mailto:[email protected]> > http://phenix-online.org/mailman/listinfo/phenixbb > Unsubscribe: phenixbb-leave(a)phenix-online.org<mailto:[email protected]> <AutoBuild_run_85_1.log><III-40-C2_justscan3_xscale_cutresto29.mtz><PAH.fa><PAH_C2_ref22plus_refine_84.pdb>

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Autobuild iterative omit map error
by Emilia C. Arturo (Emily) 21 Feb '15

21 Feb '15

Hello. I'd like to use phenix's Autobuild iterative omit map tool, but have run into an error I could use some help with. When the process aborts, the message that phenix outputs is that the input file has duplicate chains. I looked at the pdb file and I do not see duplicate chains; could the ANISOU records for each atom generated by TLS refinement be hanging up the process? I had no error with Autobuild when I started the iterative map process using an input file that had been generated by phenix.refine using the same configuration as the TLS refinement had used (except, of course, for the TLS parameters). Thanks for your attention. Emily.

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on Bulk-solvent and scaling
by Smith Lee 21 Feb '15

21 Feb '15

Dear All, Will you please introduce to me briefly on the function of the step of Bulk-solvent and scaling in the Phenix refine and what is the corresponding mechanism? Smith

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On Phenix refinement
by Smith Liu 21 Feb '15

21 Feb '15

Dear All, The default number of cycles for the Phenix refinement graphical interface is 3 (should be macro-cycles). I have done a refinement with 3 default cycles, and I get the acceptable refinement results. Then I kept everything same, except I changed the cycles of refinement from 3 to 5, however the refinement result was ugly which was unacceptable (Rfree increased). The Phenix document regards 5 macrocycles refine is fine. For my situation, do you think the 3 macrocycles refine result is acceptable or not? If not acceptable, what do you suggest for improvement? I am looking forward to getting your reply. Smith

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