- phenixbb - phenix-online.org

2nd announcement: 2013 workshop on Neutron Scattering Applications in Structural Biology
by Meilleur, Flora 02 Apr '13

02 Apr '13

4th Workshop on Neutron Scattering Applications in Structural Biology Oak Ridge, TN (USA). June 24 – June 28, 2013 Application deadline: April 22, 2013 No registration fee. Travel and accommodation grants available for participants from U.S. institutions. Detailed information available at: http://neutrons.ornl.gov/conf/gcnb2013/ Best Regards, Flora Meilleur, Ph. D Assistant Professor, Molecular and Structural Biochemistry North Carolina State University Neutron Sciences Directorate Oak Ridge National Laboratory Phone: 865-242-5747

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Fitting ligand using coot
by bsubedi＠btk.fi 31 Mar '13

31 Mar '13

Hi all, I tried to fit the ligand using the coot -> calculate-> other modeling tools-> Find ligands. I have imported cif to coot and also opened the pdb file of my ligand. However, coot do not identify the ligand and asks to adjust r.m.s.d. I can see the density for my ligand. Could anyone suggest me what could be the problem or if I am missing anything here. Best regards. Bishwa

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Re: [phenixbb] question about FFT map coefficients
by Michael Thompson 29 Mar '13

29 Mar '13

Hi Nat, The FFT didn't work out, but I'm not sure if it's due to negative Fs. When I set up the FFT map coefficients utility with my mtz file, after picking my input I get a warning that "The reflections file does not appear to contain any suitable map coefficients." Then if I try to run it anyway I get the error message "There are no map coefficients in this MTZ file." An mtz dump confirms that I have columns FP and SIGFP. Additional info: these Fs were generated using a python script that I wrote, and there are not meaningful values for SIGFP. My script simply wrote out 0.000 to the SIGFP column for each reflection essentially as a place holder. I thought that maybe 0 was not a valid entry for SIGFP so I changed it to 0.001 so there would be some value there, but I get all the same errors. Could this be the problem? Any suggestions? Thanks for the help. Sorry to bug you. Mike ----- Original Message ----- From: "Nathaniel Echols" <nechols(a)lbl.gov> To: "PHENIX user mailing list" <phenixbb(a)phenix-online.org> Sent: Thursday, March 28, 2013 3:42:31 PM GMT -08:00 US/Canada Pacific Subject: Re: [phenixbb] question about FFT map coefficients On Thu, Mar 28, 2013 at 3:28 PM, Michael Thompson <miket(a)chem.ucla.edu> wrote: > I have an mtz file with map coefficients that are essentially Fo-Fo for two data sets. I would like to generate a map using these coefficients, but because the subtraction of Fs has already been done, there are some values of FP that are negative. Is "FFT map coefficients" able to handle negative values for FP? My guess would be that the answer is yes, because internally the amplitudes and phases for map calculation are combined to form a single array of complex numbers, and this effectively converts the amplitudes to be all-positive. Also, if this were not the case, the isomorphous or anomalous difference maps would never work. But I haven't actually tried what you're wanting to do with real data - if the result isn't what you expect, let us know. -Nat _______________________________________________ phenixbb mailing list phenixbb(a)phenix-online.org http://phenix-online.org/mailman/listinfo/phenixbb -- Michael C. Thompson Graduate Student Biochemistry & Molecular Biology Division Department of Chemistry & Biochemistry University of California, Los Angeles miket(a)chem.ucla.edu

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question about FFT map coefficients
by Michael Thompson 28 Mar '13

28 Mar '13

Hello All, A quick question about the "FFT map coefficients" utility in the GUI: I have an mtz file with map coefficients that are essentially Fo-Fo for two data sets. I would like to generate a map using these coefficients, but because the subtraction of Fs has already been done, there are some values of FP that are negative. Is "FFT map coefficients" able to handle negative values for FP? If not, I can always change the sign of negative Fs and add 180 to the corresponding model phases, but I was hoping I could avoid this. Thanks in advance for the help! Mike P.S. I do know there is an Fo-Fo map option in phenix, but the origin of my map coefficients is more complicated than simply Fo-Fo, so I cannot use this option. -- Michael C. Thompson Graduate Student Biochemistry & Molecular Biology Division Department of Chemistry & Biochemistry University of California, Los Angeles miket(a)chem.ucla.edu

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suggested usage of qsub?
by Scott Classen 28 Mar '13

28 Mar '13

Hi all, We have a HPC cluster configured with TORQUE/MAUI. I see in the Phenix GUI that there is some sort of ability to queue jobs to run via qsub. I can't find any documentation on how to set this up. If I'm working at my office computer and I want to submit to a remote server cluster for refinement, is this possible? Or is it assumed that qsub is available on the local machine? Thanks, Scott

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fwd: Deadline for the CCP4 Summer School application is approaching
by Nathaniel Echols 26 Mar '13

26 Mar '13

> ---------- Forwarded message ---------- > From: "Ruslan Sanishvili (Nukri)" <nukri(a)aps.anl.gov> > To: phenixbb(a)phenix-online.org > Date: Tue, 26 Mar 2013 11:52:44 -0500 (CDT) > Subject: Deadline for the CCP4 Summer School application is approaching > Dear Colleagues, > > The deadline for applications for the 6th annual CCP4 Summer School “From data collection to structure refinement and beyond” is only ten days away. Please submit your applications before April 5, 2013. The school will take place from June 18 to June 26, 2013 at the Advanced Photon Source (APS) near Chicago. > > There is no registration fee for the school. The students will be responsible for their own travel and lodging expenses. These and other details (the program, the list of speakers, the application process, accommodations, site access, contacts etc) can be found at the workshop website at http://www.ccp4.ac.uk/schools/APS-2013/index.php > > The school will include data collection, processing, structure solution, model building, refinement, validation, automation of many steps etc. Participants are encouraged to bring their own crystals, raw data or processed data for hands-on problem solving under the guidance of software developers and other experts. > We hope to see you in June > > Garib, Ronan and Nukri > > > > Ruslan Sanishvili (Nukri) > Macromolecular Crystallographer > GM/CA@APS > X-ray Science Division, ANL > 9700 S. Cass Ave. > Argonne, IL 60439 > > Tel: (630)252-0665 > Fax: (630)252-0667 > rsanishvili(a)anl.gov > >

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low-res. real-space refinement
by "Weiergräber, Oliver H." 26 Mar '13

26 Mar '13

Hello, when refining a protein structure against a low-resolution dataset (5 A), I wanted to also attempt real-space refinement. However, in the log file I find: |-real space refinement (target=simple)---------------------------------------| rejected... | | | --------------------------------------------------------------------------- | Changing the target to, e.g., diff_map does not change anything; the message will still refer to the "simple" target. I guess this is due to an internal resolution limit, but that's only speculation since it seems to be undocumented. Indeed, there is probably not much to be gained by real-space refinement at this resolution (at least not in terms of side-chain conformations), but I wanted to give it a try anyway. Any comments on this issue? Regards, Oliver ================================================ PD Dr. Oliver H. Weiergräber Institute of Complex Systems ICS-6: Structural Biochemistry Tel.: +49 2461 61-2028 Fax: +49 2461 61-9540 ================================================ ------------------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------------------ Forschungszentrum Juelich GmbH 52425 Juelich Sitz der Gesellschaft: Juelich Eingetragen im Handelsregister des Amtsgerichts Dueren Nr. HR B 3498 Vorsitzender des Aufsichtsrats: MinDir Dr. Karl Eugen Huthmacher Geschaeftsfuehrung: Prof. Dr. Achim Bachem (Vorsitzender), Karsten Beneke (stellv. Vorsitzender), Prof. Dr.-Ing. Harald Bolt, Prof. Dr. Sebastian M. Schmidt ------------------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------------------

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Drag drop files
by Colin Levy 25 Mar '13

25 Mar '13

Hi all, I am running 1.8.2-1309 under OSX 10.7.5 but I lost the ability to drag and drop files between various phenix windows. Anyone else experiencing this or is it something specific to my setup? Thanks, Colin Manchester Protein Structure Facility MIB 1.025 Tel 0161 306 5185 c.levy(a)manchester.ac.uk<mailto:[email protected]>

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Refinement of B-factors at low resolution
by Florian Brückner 25 Mar '13

25 Mar '13

Dear all I am refining a structure at 3.2 A with phenix.refine using automatic optimization of target weights, solved by molecular replacement with a 2.1A structure of the same crystal form. Rwork=26%, Rfree=28%. I use individual atomic B-factor refinement. The obtained distribution of B-factors after refinement looks reasonable and quite similar to the distribution in the higher resolution model, which I suppose would be expected, since it is the same crystal form. However, the average B-factor does not change substantially, i.e. if I start with the B-factors from the high resolution model (average B-factor around 32 A**2) after 6 macrocycles the average B-factor is still around 32 A**2. If I set all B-factors to the Wilson B-factor determined by phenix.refine (66 A**2), after 6 macrocycles the distribution of B-factors looks again very similar to the high resolution MR model, but the average B-factor is still around 65 A**2. What should I make of this? Is this an expected behavior at this resolution, i.e. the fact that the absolute values of B-factors cannot be determined during refinement, although a reasonable distribution can be obtained as judged by plotting average B-factors vs. residue#? Since the average B-factor does not change much during refinement, which average B-factor should I start refinement with to end up with reasonable absolute values? I have manually determined the Wilson B-factor from the linear part of the Wilson plot (4.5-3.2 A) to be 97 A**2. This seems high to me. Would that be expected for the given resolution, given that the 2.1A structure of the same crystal form has 32 A**2? I should add, that there is not a substantial effect of the average refined B-factor on Rfree. Thanks for any comments or suggestions. Best regards Florian ------------------------------------------------------------- Dr. Florian Brückner Laboratory of Biomolecular Research (LBR) OFLG/102 Paul Scherrer Institut CH-5232 Villigen PSI Switzerland Tel.: +41-(0)56-310-2332 Email: florian.brueckner(a)psi.ch

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molecular replacemnt problem
by Appu kumar 24 Mar '13

24 Mar '13

Dear members, I am doing a molecular replacement of a transcription factor whose ligand binding structure(24000 Da) is available in PDB but not for the DNA binding(13000 Da). When i am searching for the two copies from ligand binding domain as a template model, i am getting very good solution but i am not getting any density for the DNA binding domain to build up in density. The space gorup is P 1 21 1 (4) and unit cell parameters are Unit Cell: 57.43 69.36 105.99 90.00 90.00 90.00. Please guide me how to get the complete model structure. Table below show the matthews statistics For estimated molecular weight 37000. Nmol/asym Matthews Coeff %solvent P(2.20) P(tot) _____________________________________________________________ 1 5.71 78.46 0.00 0.01 2 2.85 56.91 0.62 0.70 3 1.90 35.37 0.37 0.29 4 1.43 13.82 0.00 0.00 _____________________________________________________________ The phaser molecular replacement gives the following table. istogram of relative frequencies of VM values ---------------------------------------------- Frequency of most common VM value normalized to 1 VM values plotted in increments of 1/VM (0.02) <--- relative frequency ---> 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 | | | | | | | | | | | 10.00 - 8.33 - 7.14 - 6.25 - 5.56 - 5.00 - 4.55 - 4.17 - 3.85 -- 3.57 --- 3.33 ------ 3.12 ---------- 2.94 **************** (COMPOSITION*1) 2.78 ----------------------- 2.63 -------------------------------- 2.50 ----------------------------------------- 2.38 ------------------------------------------------ 2.27 -------------------------------------------------- 2.17 ----------------------------------------------- 2.08 -------------------------------------- 2.00 -------------------------- 1.92 --------------- 1.85 ------- 1.79 --- 1.72 - 1.67 - 1.61 - 1.56 - 1.52 - 1.47 * (COMPOSITION*2) 1.43 - 1.39 - 1.35 - 1.32 - 1.28 - 1.25 - TABLE : Cell Content Analysis: SCATTER :N*Composition vs Probability:0|3x0|1:1,2: $$ N*Composition Probability $$ loggraph $$ 1 0.306066 2 0.00141804 $$ Most probable VM for resolution = 2.27817 Most probable MW of protein in asu for resolution = 92664.2 I have initially indexed the data in C2221 but Rfree was not decreasing so i reindexed the data in data in P121 space group keeping the Rfree flag of C2221. While analysing the symmetry mates , i found large space but no density. structure of Ligand binding domain is almost identical with 90% identity in sequence. I am stuck with this problem and don't know how to process further. I run the phenix.xtriage to evaluate the twining but it suggest no twining. When i reindex from C2221 to P21, the completeness of data reduced from 95 % to 35% whereas the map is very good and Rwork and Rfree are 26/31 for 2.2 resolution. I do not understand why the completeness of data reduced so much on reindexing. please Can anyone explain this phenomenon. Please give me your valuable suggestion. I will appreciate your effort. Thank you

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