September 2010 - phenixbb - phenix-online.org

scattering factors
by Goragot Wisedchaisri 21 Jun '11

21 Jun '11

Hi, I am new to Phenix but I have used Solve/Resolve in the past. I am currently using Phenix 1.6.2 and I have electron diffraction data to ~2A from a 300kV electron microscope that I would like to use Autobuild and phenix.refine to iteratively rebuild and refine my partial structure. I have a file containing electron scattering factors for 300kV EM that has been used successfully for refinement with CNS before for electron diffraction data. How can I tell Phenix to use electron scattering factors during refinement? I think currently Phenix has 4 choices for X-ray and neutron scattering factors but not for electron scattering. Is there a good way to implement electron scattering factors into phenix library? Any suggestions are welcome. George Wisedchaisri

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Geometry problem with sugars refined in phenix
by Tirumala Kumar Chowdary 03 Mar '11

03 Mar '11

Hi, I have refined a structure with NAGs linked to ASNs at 3 places in my structure. I used the right link definitions and the NAG definitions are from Phenix library. Phenix refined all the sugars right and made the right links between the NAGs. However, while submitting, PDB found problem with the geometry of NAGs linked to the ASN at two places. This is the issue -the atoms around C1 atom of the sugar molecule NAG A #810 and NAG A #1670 are on a plane and the C1 atom center is far off to be tetrahedral. Please, verify the chirality of C1 and provide the correct coordinates if necessary.- Any ideas on how to fix the geometry of these sugars will be of great help. Regularization and real space refine in Coot is not working or I don't know how to do it. I am looking for alternative ways to fix this problem. Thank You Tirumal

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Problem with Autobuild
by Claudia Scotti 12 Jan '11

12 Jan '11

Dear List, Sorry fo r the easy question, but I have a problem with Autobuild. I'm trying to rebuild a scFv, composed of two domains linked by a linker. I've managed to find an MR solution with a polyalanine model deprived of the loops, which is my starting model for rebuilding. I've given Autobuild three input files: the mtz, the model coordinates and the sequence of the scFv, asking to model only the beta strands and helices. Problem is that in the final model Autobuild seems to guess incorrectly the density of two beta-strands, inserting the linker there instead of the expected side chains. Any suggestions on how to correct this? Shall I manually rebuild this part to avoid problems? Or is it crucial to prevent errors, for example, that the model and the sequence are numbered so that they are in register? Thanks in advance, Claudia Claudia Scotti Dipartimento di Medicina Sperimentale Sezione di Patologia Generale Universita' di Pavia Piazza Botta, 10 27100 Pavia Italia Tel. 0039 0382 986335/8/1 Facs 0039 0382 303673 _________________________________________________________________ Hotmail: Trusted email with powerful SPAM protection. https://signup.live.com/signup.aspx?id=60969

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Can PHENIX write the peak list to a PDB file?
by Joe Krahn 04 Dec '10

04 Dec '10

PHENIX has an option to find positive and negative peaks, but only lists them in the log file along with the residue they are closest to. Is it possible to write out the actual peak coordinates, such as to a PDB file? Thanks, Joe Krahn

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Bad ligand parameters
by Joe Krahn 21 Oct '10

21 Oct '10

I found that residue TRS has different dihedral target angles for the three hydroxyl oxygens, which are actually all equivalent. They have a periodicity of 1, but should have a periodicity of 3. What is the best way to handle such discrepancies? Most ligand parameters are probably auto-generated based on a reference structure, and there is probably a lot of conformation bias. In this case, it seems that parameterization should have been able to detect symmetry. It would be nice if parameters could include information about whether a human has done any validation. Actually, a ligand Wiki might be nice, where people can easily put comments, even if they are not sure about how to improve the parameters. Joe Krahn

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Re: [phenixbb] Help on multi-start-simulated-annealing sigmaA-weighted 2fofc map - WORKING EXAMPLE
by Pavel Afonine 03 Oct '10

03 Oct '10

Hi Fengyun, no problems, here is the updated script and inputs files to illustrate how it works: http://cci.lbl.gov/~afonine/mssa2/ All it needs is a bunch of PDB files and corresponding map coefficients. Let me know if you have any questions. Pavel. On 9/9/10 7:48 PM, fn1(a)rice.edu wrote: > Hi Pavel, > > The script works fine. I hope you could slightly revise the script for > me. > > Since right now, I could run the multi-sa on different nodes at the > same time. So I could get the refined models in the name of sa-#.pdb > within a short time. > > So I could begin with the different models and combine them to > "all.pdb" and calculate the average map after that. But I don't know > how to revise the run.py to do that. > > Wait for your help. > Thanks! > Fengyun > > 引用 Pavel Afonine <pafonine(a)lbl.gov>： > >> Hi Fengyun, >> >> my previous email actually doens't answer your question - I realized >> this after I pushed Sent button -:) >> >> To really answer your question I just wrote a Python script that does >> the following: >> - run multi-start Simulated Annealing, >> - combine all refined models into one multi-model PDB file (models >> separated by MODEL-ENDMDL records), and >> - compute averaged 2mFo-DFc map. >> >> The complete working example is here: >> >> http://cci.lbl.gov/~afonine/mssa/ >> >> You have two options at this point: >> >> - take this example, slightly change inputs by editing the run.py >> file (change input data and model file names, number of SA runs, etc) >> and run it as following: >> >> phenix.python run.py >> >> (since I spent 15 minutes on writing this script it's obviously not >> thoroughly tested or parameter-optimized, although I believe it >> should do the job right) >> >> or >> >> - wait a few days for one of the next PHENIX nightly builds where the >> above script will be available as a user-friendly either >> phenix.multi_start_sa command or an option of phenix.maps (I haven't >> decided yet what is better). >> >> Let me know if you have any questions. >> >> Pavel. >> >>> I read on the paper that they use CNS (model_map.inp) to calculate >>> the avarage sigmaA-weighted 2fofc map. Right now I have set up the >>> simulated annealing with different random seeds. I wonder whether >>> phenix could calculate the average map with the multiple coordinates >>> from different starts? >> >> >> > > >

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question on the weight for adp
by fn1＠rice.edu 30 Sep '10

30 Sep '10

Hi everyone, I have some questions the weight for adp. My case is that some part of the model will be refined to large B values (about 100) if the default value of wxu_scale (1.0) is used. The other part of the model will have average B value of about 40, which the wilson B is about 35. The corresponding 2FOFC map has very poor density for the region with large B values. If the value of wxu_scale set to be 0.1, that part with large B will be refined to about 80 for B. The corresponding 2FOFC map has some better (but not good enough) density for this region. My question is that can I keep the wxu_scale at the small value for the refinement? Or finally do I need to loose this value? Thanks! Fengyun

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Seeking Postdoctoral Researcher
by Francois Berenger 30 Sep '10

30 Sep '10

Laboratory: Zhang Initiative Research Unit, Advanced Science Institute, RIKEN, Japan. (Unit Leader: Dr. Kam Zhang) Job title and Job description: Postdoctoral Researchers Job description: We are seeking a highly motivated and experienced computational structural biologist to join the Zhang Initiative Research Unit at RIKEN. The successful candidate will use computational tools to tackle problems in the area of protein folding, structure prediction, and structure-based drug design. Our ability to predict the structure of proteins from their primary sequences will greatly facilitate our understanding of the important biological functions that proteins play in their host systems. The 3D structure information will also facilitate the rationale design of drugs for the treatment of various diseases with unmet medical needs. Qualifications: This position requires a PhD in areas related to biophysics, biochemistry, computational chemistry, bioinformatics, or structural biology with experience in employing computational tools to solve biological or chemical problems. Experiences in protein folding, protein structure prediction, protein structure analysis, protein crystallography, or structure-based drugs are highly desired. Proficiency in object-oriented programming such as C++, Java, scripting languages such as Python, Perl are also desired. Experiences in high performance computing, network computing, or grid computing would be a plus. The ideal candidate should possess a track record of accomplishments demonstrating technical proficiency, independent thinking, and scientific creativity. The research environment will be international and hence communication in English is encouraged. The complete job ad, as well as how to apply can be viewed here: http://www.riken.jp/engn/r-world/info/recruit/k100817_s_asi.html Best regards, Francois.

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Ligand restraints editing with REEL -summary
by Joseph Brock 29 Sep '10

29 Sep '10

Hi all, I just wanted to post a quick summary of how my problem was resolved. I later realised that the 'native glutahione' molecule I was transferring ligand restraints from was actually produced by eLBOW released under the Phenix package v1.4, and was therefore defined differently to those restraints created by v1.6.4-486. I was advised by Nigel (author of eLBOW and REEL) to download the latest nightly build (dev-541) and create a clean subdirectory. Copying my model.pdb and data.mtz file into this, running phenix.ready_set on these files and running phenix.refine with the resulting .pdb and .cif files, resulted in a ligand that was correctly restrained to refine into the density extremely well. Hope this is of help to anyone with a similar problem. Cheers, Joe. > From: phenixbb-request(a)phenix-online.org > Subject: phenixbb Digest, Vol 58, Issue 18 > To: phenixbb(a)phenix-online.org > Date: Sat, 18 Sep 2010 12:00:01 -0700 > > Send phenixbb mailing list submissions to > phenixbb(a)phenix-online.org > > To subscribe or unsubscribe via the World Wide Web, visit > http://phenix-online.org/mailman/listinfo/phenixbb > or, via email, send a message with subject or body 'help' to > phenixbb-request(a)phenix-online.org > > You can reach the person managing the list at > phenixbb-owner(a)phenix-online.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of phenixbb digest..." > > > Today's Topics: > > 1. Ligand restraints editing with REEL (Joseph Brock) > 2. Re: Ligand restraints editing with REEL (Ralf W. Grosse-Kunstleve) > 3. Resolve NCS masks (Florian Schmitzberger) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Sat, 18 Sep 2010 08:09:23 +0000 > From: Joseph Brock <joeylives2ride(a)hotmail.com> > To: <phenixbb(a)phenix-online.org> > Subject: [phenixbb] Ligand restraints editing with REEL > Message-ID: <SNT120-W580E16EA4DC524ED59A3209B7C0(a)phx.gbl> > Content-Type: text/plain; charset="iso-8859-1" > > > Hi all, > > I'm working on a 1.5A structure that contains a novel ligand within the active site, which is an Arsenic derivative of Glutathione, using the Phenix GUI, version 1.6.4-486. > > I have been using the 'Molinspiration' webpage (http://www.molinspiration.com/docu/webme/) to generate a smiles string, which I then feed into ELBOW. Although the structure/chemical restraints of Glutathione should be unchanged by the covalent linkage to arsenic through the cysteinyl sulfur, the resulting restraints file consistently restricts one of the dihedrals to a value that is incompatible with the (quite clear) electron density. This occurs regardless of wether i use AM1 optimization, and is unresponsive to using native Glutathione (which refines into the corresponding density extremely well) as an input geometry file with any of the available 'Use geometry for' options (final geometry, initial geometry, etc). > > I then tried opening the output file in REEL and manually changing the corresponding dihedrals to those of glutathione, however after running simple optimization, the resulting restraints file has the same problem, and upon choosing the 'transer geometry and restraints' option (or any option) midway through running the 'eLBOW optimization' or 'AM1 optimization' options, Phenix consistently crashes. > > Any advice on how to transfer the origional geometry of native Glutathione to my new ligand effectively would be greatly appreciated. I'm a little confused as to the abilities of REEL, and how to affect them. > > Thanks so much in advance. > > Cheers, > > -Joe. > > >

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mlhl refinement
by Florian Schmitzberger 28 Sep '10

28 Sep '10

Dear All, I am running Phenix version 1.6.4.-486 on imac. I just wanted to refine (phenix.refine) a model with MLHL target and experimental phase information. Strange thing is when I load the mtz file, as written out from Phenix Autosol (overall_best_denmod_map_coeffs.mtz) into the GUI, the Phenix refine GUI does not seem to any phase information. Only picks up FP and SIGFP labels; but not the Hendrickson-Lattman coefficients, which are present. The following message comes up when I try to chose mlhl refinement: " You have selected 'mlhl' as the refinement target, but no experimental phases were supplied. If you wish to use phase restraints in refinement, please add or select experimental phases, or choose another target function". I guess it is not such a major problem as I can save the .eff file and manually edit it to include the HL coefficients and then run Phenix (as long as Phenix then recognizes them from the mtz file). I would also like to refine f' and f'', as the data are from a selenomethionine derivatized protein. From what I can see the default in Phenix.Autosol seems to be not to keep the F+/- and Dano labels for the output mtz file? So I suppose I do need to provide the initial mtz file or is there a way to change the output options for the coefficients in Phenix Autosol? Cheers, Florian ----------------------------------------------------------- Florian Schmitzberger Biological Chemistry and Molecular Pharmacology Harvard Medical School 250 Longwood Avenue, SGM 130 Boston, MA 02115, US Tel: 001 617 432 5602

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