March 2015 - phenixbb - phenix-online.org

labelit distl_minimum_number_spots_for_indexing
by Christian Roth 22 Sep '15

22 Sep '15

Dear Phenix-Team I installed the latest nightly build 1.8-1069. I tried to index some diffraction images and to overwrite the minimum usable spots for indesing I tried the suggested command. However If I try this command, it seems that it does not exist. At least in the list of the possible distl commands it does not show up. Do I have to install some additional stuff or change some preferences to get this command? Best Regards Christian

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Refinement with new mtz.file
by Aleksandar Bijelic 14 Jul '15

14 Jul '15

Dear CCP4 user and experts, I refined (with PHENIX) a 3.0 A dataset obtaining Rfree of about 0.24 (with good geometry according to Ramachandran, Beta Outliers, etc.) .... Everything seems to be ok (especially in relation to the resolution) .... because the mtz.file I used was quite old and I cannot find my xscale.hkl file, I processed the data set again (this time with optimizng and polishing) and received a "better" file according to almost everything (resolution limit, I/sigma, CC(1/2), Rmeas), thus I used this new mtz.file and put it in my last refinement step (the refinement which led to the above mentioned Rfree = 0.24). Suprisingly, the refinement starts at Rwork = 0.18 and Rfree = 0.19 but ending up with 0.20 and 0.22, respectively. So I wanted to know if this is usual? I was expecting my data to become slightlly better but what is irritating me is the starting R-values of the refinement and that it get worse during refinement. Maybe I did something wrong? Is it reasonable to replace the mtz.file with a new one in the last refinement step or should I start the refinement from the scratch? In the sake of completeness, I deleted the header of the used pdb.file because of the R-flag error which occurs, since Phenix reconizes that the pdb.file was already used with other Rflags. Sorry, but I am still a beginner in this field, so I would be very grateful if somebody could explain me this situation and my mistake and if I need to start refinement from the beginning. Thank you in advance! Best Regards. Aleksandar -- ------------------------------------------- Aleksandar Bijelic, MSc. Institut für Biophysikalische Chemie Universität Wien Althanstrasse 14 A-1090 Wien Tel: +43 1 4277 52536 e-Mail: aleksandar.bijelic(a)univie.ac.at --------------------------------------------

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Re: [phenixbb] Refinement
by Pavel Afonine 26 May '15

26 May '15

Hi Mohamed, > How do tell phenix.refine to not move my HEM ligand around? yes, you can exclude selected atoms from refinement of coordinates in Phenix refinement GUI: Refinement settings -> Modify selection for: XYZ coordinates -> Edit -> type atom selection in "Edit selected" field (under XYZ refinement) like "chain A and resseq 1" or "chain A and resname ATP" However, I would rather find why correct geometry is not preserved. > I have a cif file describing the ligand but in my case, I can see > clear density of it not following the ideal geometry. If you send me files (off mailing list of course!) I will see if I can explain it.. You can copy to Nigel too as chances are that if you choose to send files I will be talking to him anyway. > As an example, I have attached a screenshot from Coot. It's hard to infer what's going on from a static image.. > In fact, the C atom is covalently linked to the nearest Cys, so the > HEM side chain should be 'moved' into the density and the green blob > shouldn't be there. Is this link defined anywhere in restraints used in refinement? Pavel

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idealizing structure
by PC 27 Apr '15

27 Apr '15

Is there a way to "idealize" a structure in Phenix? I mean, ideal omega, all residues within allowed regions of Ramachandran maps, no clashes..etc. I know it won't fit the map well but I would like to see what it looks like. Thank you. ____________________________________________________________ FREE 3D MARINE AQUARIUM SCREENSAVER - Watch dolphins, sharks & orcas on your desktop! Check it out at http://www.inbox.com/marineaquarium

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twinning
by Shun Liu 01 Apr '15

01 Apr '15

Dear all, Recently I have got a data set that diffracts to 1.7 angstrom. Images look good. During data processing I did not find anything that looks strange. However, when I was doing Phaser-MR, I got a warning: “ Intensity moments suggest significant twinning (>5%). Tests based on possible twin laws will be more definitive.” What does this mean? A twinning data set? I still found a solution and refined the model step by step, using the data (20-1.7 angstrom). It seems that the final model and map are acceptable. But R-factors are 0.24/0.28, very high. Does the twin cause the high R-factors? Is there a solution to detwin? Or are the R-factors acceptable for a twinning data set? Any suggestions are appreciated and thanks in advance! Best, Shun

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continuously Rfree lower than Rwork
by Smith Liu 31 Mar '15

31 Mar '15

Dear All, If in a Phenix.refine proces, the Rfree continuously lower than Rwork, what does it mean? Smith

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Twinning
by Shun Liu 31 Mar '15

31 Mar '15

Dear all, Recently I have got a data set that diffracts to 1.7 angstrom. Images look good. During data processing I did not find anything that looks strange. However, when I was doing Phaser-MR, I got a warning: “ Intensity moments suggest significant twinning (>5%). Tests based on possible twin laws will be more definitive.” What does this mean? A twin data set? I still found a solution and refined the model step by step, using the data (20-1.7 angstrom). It seems that the final model and map are acceptable. But R-factors are 0.24/0.28, a little high. Does the twin cause the high R-factors? Is there a solution to detwin? Or are the R-factors acceptable for a twin data set? Any suggestions are appreciated and thanks in advance! Best, Shun

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First-Science Discussions for Life-Science Beamlines at NSLS-II: April 21-22, 2015
by Robert Sweet 27 Mar '15

27 Mar '15

We will hold a "First Science at the ABBIX Beamlines" meeting on Tuesday - Wednesday, April 21-22, 2015, pertaining to the National Institutes of Health (NIH)-sponsored "Advanced Beamlines for Biological Investigations with X-rays" (ABBIX) Project. These three state-of-the-art beamlines are now under construction at the National Synchrotron Light Source (NSLS)-II facility at Brookhaven National Laboratory (BNL). Two of the beamlines are for macromolecular crystallography (MX), and the third is for life sciences applications of x-ray scattering. Visit this web site for further information and registration materials: http://workshops.ps.bnl.gov/?w=ABBIXApr2015 Briefly, the MX beamline called FMX - Frontier MX - is optimized to address microbeam applications, and the other called AMX - Highly Automated MX - is optimized for highly automated throughput. The scattering beamline called LIX - High Brightness X-Ray Scattering for Life Sciences - will offer multiple modes of study. The MX beamlines view canted undulator sources, and the scattering beamline views a single undulator, providing world-leading brightness. Current plans are to conclude construction by the end of 2015 and start commissioning then. During the commissioning period, opportunities will arise to perform early experiments before the general user programs of the beamlines commence in 2016, and it is the upcoming meeting's purpose to explore and discuss scientific areas and opportunities on which early operation of the beamlines could capitalize. Note: Registration is required. There is no registration fee. Visit this site to register: http://workshops.ps.bnl.gov/?w=ABBIXApr2015 Those who registered for the original meeting planned for January must re-register for the new occurrence in April. Contributed presentations describing experiments that exploit the capabilities of the ABBIX beamlines will be selected from submitted abstracts. The meeting will consist of both plenary and parallel sessions. The plenary session will begin with presentations on science topics in research fields that the beamlines are designed to address, followed by facility presentations to update the community about the early scientific capabilities at the suite of ABBIX beamlines and, in addition, of the Life Science and Biomedical Technology Research Resource (LSBR), sponsored by the NIH and the Department of Energy Office of Biological and Environmental Research (DOE BER). Two parallel sessions on Tuesday afternoon will focus on MX and x-ray scattering, consisting mainly of presentations that will address specific opportunities in these areas. These will be followed by two more parallel sessions on Wednesday morning, also focusing on MX and x-ray scattering, which will include contributions. If you wish to give a contributed presentation during one of the parallel sessions, please submit an abstract here: http://workshops.ps.bnl.gov/abstracts/default.aspx?w=ABBIXApr2015 The parallel sessions are designed to provide forums to facilitate more detailed discussions about potential first experiments at specific beamlines and the formation of the experiment teams. Specifically, each parallel session group will be charged to accomplish these goals: 1. Identify key research projects and the associated first experiments that may be performed at the suite of ABBIX beamlines, emphasizing those projects that will take advantage of NSLS-II properties and ABBIX beamline capabilities. 2. Facilitate the formation of research teams to generate first experiment proposals for submission. 3. Identify key additional team members in such areas as theory and analysis, ancillary measurements, and specimen preparation, needed to achieve the research goals. Confirmed invited speakers: Karen Allen (Boston Univ), Martin Caffrey (Trinity College Dublin), Seth Darst (Rockefeller Univ), Richard Gillilan (Cornell Univ), Wayne Hendrickson (Columbia Univ), AndrHoelz (California Inst Tech), Huey Huang (Rice Univ), Shenping Liu (Pfizer), Lee Makowski (Northeastern Univ), David Ostrov (Univ of Florida), Rebecca Page (Brown Univ), Anna Marie Pyle (Yale Univ), Christian Riekel (ESRF), Thomas Schneider (EMBL-Hamburg), John Tainer (Scripps Research Inst). We would like two outcomes from this meeting: (a) a concise meeting report outlining how ABBIX beamlines will help to address outstanding problems in life sciences, and (b) a list of potential first experiments along with the corresponding research teams. For more information on the meeting, please contact Sonya Kiss, at skiss(a)bnl.gov. Note: Registration deadline is Tuesday, April 14, 2015. Organizers: Lonny Berman ABBIX Project Manager National Synchrotron Light Source II Brookhaven National Laboratory Sean McSweeney Structural Biology Program Manager Photon Sciences Division Deputy Director National Synchrotron Light Source II

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can mr_rosetta include twin_law?
by Ni, Fengyun 27 Mar '15

27 Mar '15

Hi everyone, When I run phenix.mr_rosetta, I use the following file (twin.eff) to add the twin_law with the keyword: refinement_params=twin.eff. I checked the output that the phenix.refine stage could recognize this file. But the autobuild step can not read this file and give the error information as follows, refinement.twinning { twin_law = "h,-h-k,-l" } Unable to read the parameters file twin.eff. Is there anyway to overcome this issue? Thank you very much in advance! Fengyun

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Refinement
by mohamed noor 26 Mar '15

26 Mar '15

Dear all I have a structure at 1.4 A currently with an Rfactor of 21/26 %. I notice from the plot by cycle that everytime the RMS bonds/angles reduce, the Rfactor increases a few percent. Is there any way of telling phenix.refine to not 'restrain' the model too much? I have already used automatic weighting. Also, RINGER identified a few alternate conformations, so I'm thinking that modeling this might account for a better model. However, as I have an NCS of 4, this can be tedious to do by hand, and AFAIK, phenix.refine does not create new conformations. Is there an alternative? Final question, some residues were flagged as having high B factors but not in all the copies. How do I deal with this? Some background: I initially had problems with refinement being stuck at 30-35 % in SG P 3 2 1 (as suggested by Pointless and Xtriage). However, the beamline scientist suggested that there could've been lattice translocation and that it is actually P 3. Reintegrating seems to have solved the problem. With integrated data up to 1.2 A, I tried cut-off at 1.4, 1.3 and 1.2 A. Together with CC1/2 and refinement results, I chose 1.4 A, but should I cut it a bit lower? Thanks.

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