- phenixbb - phenix-online.org

need subscription
by Afshan Begum 03 Jul '12

03 Jul '12

Dear Sir I have subscribe successfully to the phenixbb but i have not receive or involved in the discussion board could you kindly help ? Best Regards AFSHAN

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Question about mr-sad
by Edward A. Berry 02 Jul '12

02 Jul '12

in doing SAD phasing with the option: input_partpdb_file=MR.pdb Is it assumed MR.pdb is already located in the cell, or is it a model to be used in MR assisted by information from the heavy atom sites? Thanks, eab

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Re: [phenixbb] Default anisotropic B-factor refinement in phenix.refine?
by Filip YABUKARSKI 02 Jul '12

02 Jul '12

Hello again, First thank you very much for the response But in this case after the second run of phenix.refine i will lose the TLS contribution and the anisoU lines (?). How am I supposed to continue with TLS then (given it lowers my R factors i would be happy to keep it) and be sure that i do not refine anisotropic ADPs? Or you mean that i can do the 2 consecutive runs (with and without TLS) in the end of the refinement? Sorry if I got something wrong Filip On 2012-07-02 18:58, Pavel Afonine wrote: > Hi Filip, > > phenix.refine manual may need an update.. > > At 3A resolution if you run two consecutive refinements first with > TLS and the next one without TLS then in the second run anisotropic > ADPs will be converted to isotropic automatically. This is done by > phenix.refine to prevent accidental refinement of individual > anisotropic ADPs in such cases. The keyword and threshold are: > switch_to_isotropic_high_res_limit=1.5. > > Pavel > > On 7/2/12 9:47 AM, Filip YABUKARSKI wrote: >> Hello, >> >> I recently started to refine a structure with phenix.refine for a >> first time. It is a 3A dataset with NCS of 8. For the refinement i >> wanted to use TLS groups as well as individual B-factors >> (data/parameter ratio should be fine with ncs of 8) and after several >> cycles of refinement i get the Rfac of 20 and Rfree of 24 which is >> quite good (i also use simulated annealing, Secondary structure >> restraints and NCS restraints). Re-reading the refinement manual I >> realized that by using a PDB file which comes from a phenix.refine >> with TLS in the next refinement i am probably doing an anisotropic >> B-factor refinement for each atom, which in my case is not justified. >> I found a post on ccp4bb from 19 Fev 2009 discussing this issue but >> for me it is still not very clear. By reading the PDB i got from >> phenix.refine (version 1.7.3) it is not very clear (at least for me) >> if the refinement was with TLS groups and individual isotropic >> B-factors or with anisotropic B-factors. Basically my question is: if >> the input PDB has already anisoU records from a previous phenix.refine >> with TLS groups is the new phenix.refine going to use isotropic >> individual B-factors or anisotropic ones? (Even if in my case one can >> assume that i can probably use anisotropic B-factor refinement (24000 >> unique reflections with ncs of 8 vs. 6000 atoms in total) this is >> rarely the case for non-atomic resolution datasets) I would be very >> happy if someone gives an explanation. Many thanks >> >> Cheers >> Filip

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Default anisotropic B-factor refinement in phenix.refine?
by Filip YABUKARSKI 02 Jul '12

02 Jul '12

Hello, I recently started to refine a structure with phenix.refine for a first time. It is a 3A dataset with NCS of 8. For the refinement i wanted to use TLS groups as well as individual B-factors (data/parameter ratio should be fine with ncs of 8) and after several cycles of refinement i get the Rfac of 20 and Rfree of 24 which is quite good (i also use simulated annealing, Secondary structure restraints and NCS restraints). Re-reading the refinement manual I realized that by using a PDB file which comes from a phenix.refine with TLS in the next refinement i am probably doing an anisotropic B-factor refinement for each atom, which in my case is not justified. I found a post on ccp4bb from 19 Fev 2009 discussing this issue but for me it is still not very clear. By reading the PDB i got from phenix.refine (version 1.7.3) it is not very clear (at least for me) if the refinement was with TLS groups and individual isotropic B-factors or with anisotropic B-factors. Basically my question is: if the input PDB has already anisoU records from a previous phenix.refine with TLS groups is the new phenix.refine going to use isotropic individual B-factors or anisotropic ones? (Even if in my case one can assume that i can probably use anisotropic B-factor refinement (24000 unique reflections with ncs of 8 vs. 6000 atoms in total) this is rarely the case for non-atomic resolution datasets) I would be very happy if someone gives an explanation. Many thanks Cheers Filip

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Postdoctoral Fellow & Scientific Officer / Higher Scientific Officer Positions at ICR, London, UK
by Sebastian Guettler 30 Jun '12

30 Jun '12

Dear PHENIX Community, We are currently looking for two motivated researchers to join our new, exciting research programme on the regulation and functions of ADP-ribosyltransferases: one Scientific Officer / Higher Scientific Officer and one Postdoctoral Fellow. Please see the job descriptions for the two positions and instructions on how to apply below. Best wishes, Sebastian Postdoctoral Fellow & Scientific Officer / Higher Scientific Officer Positions at ICR, London, UK In the Divisions of Structural and Cancer Biology of the Institute of Cancer Research (ICR; http://www.icr.ac.uk), our new team led by Dr. Sebastian Guettler has a vacancy for a Scientific Officer or early-career Higher Scientific Officer and a Post-doctoral Training Fellow. Research in the Divisions of Structural and Cancer Biology focuses on the functional, biochemical, and structural characterisation of cellular processes relevant to cancer and cancer therapy. The Division of Structural Biology, where the laboratory will be physically based, has managed facilities for protein crystallography (crystallisation robots, x-ray diffractions systems), cryo-electron microscopy and protein production with expertise in multi-subunit expression systems (bacterial, yeast and insect cell expression, including a 60-litre fermentor). The Division is also well equipped with instrumentation for biophysical analysis (e.g., ITC, fluorescence-based methods, multi-angle light scattering). The Division of Cancer Biology provides a state-of-the-art infrastructure for mammalian cell culture, imaging, mammalian genetics, chemical biology and proteomics. Position 1: Post-doctoral Training Fellow (job reference number 1257974) Closing date of vacancy: 6 July 2012 Starting date of position: mid-October / early November 2012 Division: Structural Biology & Cancer Biology Team: Guettler Group Type of contract: fixed term Length of contract: 3 years in the first instance Salary range: £27,536 to £33,852 p.a. inclusive (depending on previous post-doctoral experience) Work location: London (Chester Beatty Laboratories, Chelsea) The successful applicant will undertake biochemical, crystallographic and functional studies on members of the ADP-ribosyltransferase (or “PARP”) family of proteins and their regulators. Our goal is to gain insight into the control and cellular roles of these enzymes with a specific interest in ADP-ribosyltransferase-dependent signalling processes linked to cancer. Applicants should possess a PhD (or equivalent) in biochemistry or molecular biology and a sound knowledge of protein purification for structural analyses. Experience with recombinant DNA techniques, protein expression and purification as well as protein crystallography is essential. Experience in mammalian cell culture, enzymology or protein production in insect cells (MultiBac) would be of advantage. For further details and instructions on how to apply, please refer to our online vacancy and recruitment site at http://www.icr.ac.uk/jobsearch, quoting job reference number 1257974 for this position. While applications need to be placed via our online system, informal inquiries can be sent to Dr. Sebastian Guettler at sebastian.guettler(a)icr.ac.uk. Position 2: Scientific Officer / Higher Scientific Officer (job reference number 1260528) Closing date of vacancy: 20 July 2012 Starting date of position: mid-October / early November 2012 Division: Structural Biology & Cancer Biology Team: Guettler Group Type of contract: fixed term Length of contract: 3 years in the first instance Salary range: £23,000 to £29,545 p.a. inclusive (depending on skills and experience) Work location: London (Chester Beatty Laboratories, Chelsea) The objective of this post will be to provide support within Dr. Guettler's laboratory for research into the structure and function of proteins. The post holder will work as a member of a multidisciplinary team investigating the functions and regulation of ADP-ribosyltransferases. The work will involve the production and purification of proteins and protein complexes, their characterisation, crystallisation and functional analysis. Applicants should minimally possess a BSc (or equivalent) in molecular biology, biochemistry or cell biology. Experience in molecular cloning, recombinant protein expression in E. coli and large-scale, crystallisation-grade protein purification is essential. Experience with protein production in insect cells (MultiBac) and mammalian cell culture would be of advantage. For further details and instructions on how to apply, please refer to our online vacancy and recruitment site at http://www.icr.ac.uk/jobsearch, quoting job reference number 1260528 for this position. While applications need to be placed via our online system, informal inquiries can be sent to Dr. Sebastian Guettler at sebastian.guettler(a)icr.ac.uk. The Institute of Cancer Research: Royal Cancer Hospital, a charitable Company Limited by Guarantee, Registered in England under Company No. 534147 with its Registered Office at 123 Old Brompton Road, London SW7 3RP. This e-mail message is confidential and for use by the addressee only. If the message is received by anyone other than the addressee, please return the message to the sender by replying to it and then delete the message from your computer and network.

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k_sol and b_sol
by Luca Pellegrini 28 Jun '12

28 Jun '12

Hello, Where do I find the minimised values of k_sol and b_sol in phenix.refine? For some reason, they are not included in REMARK 3 of the pdb file after refinement, and I can't find them in the log file. Thanks, Luca Luca Pellegrini Department of Biochemistry University of Cambridge 80 Tennis Court Road Cambridge CB2 1GA - UK Email: lp212(a)cam.ac.uk Tel: 0044-1223-760469 Fax: 0044-1223-766002 Sanger building, room 3.59

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Incorrect solvent modelling in Phenix.refine?
by David Briggs 28 Jun '12

28 Jun '12

Hi all, I'm refining a couple of structures of the same protein (well, point mutants) and I am consistently seeing large (6sig) negative difference map peaks within some cavities within my protein, present in both the datasets. As far as I understand, this is because the bulk solvent scaling parameters are either incorrect, or being incorrectly applied. I have tried a few things like applying the "Refine solvent mask (slow)" options, all to no avail. Resolution is 2.2Å and 2.5Å. Experimental phasing, Xtriage reports no abnormalities in the data. Is there anything that I am missing? Do I need to worry about this? Regards, Dave ============================ David C. Briggs PhD Father, Structural Biologist and Sceptic ============================ University of Manchester E-mail: david.c.briggs(a)manchester.ac.uk ============================ Webs : http://flavors.me/xtaldave Twitter: @xtaldave Skype: DocDCB ============================

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Error in phenix.autobuild
by Tanner, John J. 27 Jun '12

27 Jun '12

Can anyone shed light on the error below? The situation is that I have a ~90% complete model from refinement (r_work = 0.2415, r_free = 0.3167), and I want phenix.autobuild to build the rest of the structure. I issued this command: phenix.autobuild data=../ccp4/DrPRODH3-6_1_scala2.6Ang.mtz model=Refine_9/DrPRODH_refine_9.pdb seq_file=../seq/DrPRODH-noMet1.fasta rebuild_in_place=False nproc=3 I got this error: [tannerjj@europa AutoBuild_run_2_]$ tail -n20 AutoBuild_run_2_1.log Output space group: P 1 21 1 (No. 4) Columns of data in AutoBuild_run_2_/refinement_PHX.mtz: H K L FreeR_flag F_DrPRODH3-6 SIGF_DrPRODH3-6 Unit cell: (46.806, 95.875, 70.504, 90, 107.733, 90) Space group: P 1 21 1 (No. 4) Using AutoBuild_run_2_/refinement_PHX.mtz for refinement Correcting data file /titan/tanner/DrPRODH/ccp4/DrPRODH3-6_1_scala2.6Ang.mtz for anisotropy and writing to AutoBuild_run_2_/aniso_data_PHX.mtz Getting overall aniso B from datafile... *************ERROR ENDING ******************* **************************************** AutoBuild Input failed iotbx InternalError: /net/longnose/scratch2/phenix/phenix-1.7.3-928/cctbx_project/iotbx/mtz/dataset.cpp(97): IOTBX_ASSERT(strlen(label) < sizeof(column_ptr->label)) failure. **************************************** *************ERROR ENDING *******************

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occupancy group definition
by Christian Roth 26 Jun '12

26 Jun '12

Dear All, I have tried an occupancy refinement for a partially modifed residue. I have split the residue in altloc A and B and the modification (PMSF) is attached on B. I included the PMS moiety as part of the residue and gave them altloc B. I created the cif link. The refinement resulted in a strange mixture of occupancys for PMS around 0.8 and both Serins 0.23 an 0.77. So PMS is not part of the residue. I am not sure about the correct syntax for the constrained group. At the moment I have used constrained_group { selection = chain A and resseq 130 and altloc A selection = chain A and resname PMS and altloc B } However the Serine pat of altloc B refines to a value not compatible to the PMS values or the Altloc A value of the serine. How do I incorporate the altloc B for the serine? Thanks in advance for your help Christian

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geometry weight help
by 周文昌 25 Jun '12

25 Jun '12

Dear all, Last week, I played a little bit with geometry weight in phenix refinement. When I check the log file, what I found is that if I use wxc_scale and fix_wxc in my refinement, actually phenix will ignore the wxc_scale, while if I only use wxc_scale, phenix will follow the value specified in the command line, but the wxc value will change from one macro cycle to another cycle. Below shows one of my examples in which the wxc_scale values are ignored when I use wxc_scale and fix_wxc at the same time. Anyone has similar problems? Thanks for all your considerations. ################## Command line arguments: "../new-unique.mtz" "../3tx8.pdb" "fix_rotamers=true" "strategy=individual_adp+individual_sites" "wxc_scale=0.01" "refinement.input.xray_data.labels=FP,SIGFP" "fix_wxc=10" "--overwrite" refinement.target_weights.wxc_scale = 0.01 refinement.target_weights.fix_wxc = 10 wxc_scale = 0.01 fix_wxc = 10 | XYZ refinement: T = Eexperimental * wxc * wxc_scale + Echem * wc | | wxc = 10.000000 wxc_scale = 1.000 wc = 1.000 | ... ################## Wenchang

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