- phenixbb - phenix-online.org

Fwd: Re: Sculptor
by Gabor Bunkoczi 08 Sep '14

08 Sep '14

Apologies, this was meant for the BB. -------- Original Message -------- Subject: Re: [phenixbb] Sculptor Date: 2014-09-08 10:41 From: Gabor Bunkoczi <gb360(a)cam.ac.uk> To: Marie Elizabeth Fraser <frasm(a)ucalgary.ca> Hi Marie, please check the extension of your alignment. If it is .pir, the second line is supposed to be a comment line, and it is therefore ignored. You can either change the extension to .ali, or insert an empty line after the ones starting with ">". If this is not the problem, then this is not supposed to happen. Please send me the logfile in the first instance, although I may need the actual alignment and the PDB file as well (you can delete the target sequence if you wish, an alignment with a single sequence is perfectly valid). BW, Gabor On 2014-09-08 01:22, Marie Elizabeth Fraser wrote: > Hello, > I'm running Sculptor from the Phenix GUI, trying to improve a > molecular replacement model. I've given the pdb file and a sequence > alignment. Sculptor does not appear to accept the first residues > aligned in the sequence alignment. In the alignment, these residues > are residue numbers 42 to 60, so they are on the second line of the > fasta file (the first line after the title) and Sculptor starts at > residue 61 (the subsequent line). Residues 42 to 60 of the target are > to match the first residues of the pdb model, so in the alignment, > there are 41 dashes before the beginning of the sequence for the pdb > file. Am I giving an incorrectly formatted sequence alignment, > misinterpreting what Sculptor does or is Sculptor supposed to do this? > Thank you, Marie > > _______________________________________________ > phenixbb mailing list > phenixbb(a)phenix-online.org > http://phenix-online.org/mailman/listinfo/phenixbb

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Sculptor
by Marie Elizabeth Fraser 07 Sep '14

07 Sep '14

Hello, I'm running Sculptor from the Phenix GUI, trying to improve a molecular replacement model. I've given the pdb file and a sequence alignment. Sculptor does not appear to accept the first residues aligned in the sequence alignment. In the alignment, these residues are residue numbers 42 to 60, so they are on the second line of the fasta file (the first line after the title) and Sculptor starts at residue 61 (the subsequent line). Residues 42 to 60 of the target are to match the first residues of the pdb model, so in the alignment, there are 41 dashes before the beginning of the sequence for the pdb file. Am I giving an incorrectly formatted sequence alignment, misinterpreting what Sculptor does or is Sculptor supposed to do this? Thank you, Marie

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refine structure with mtz file in P212121 or P222?
by Wei Shi 05 Sep '14

05 Sep '14

Hi all, I am working with a protein-ligand complex structure. The data was indexed with XDS and mtz file is generated using Phenix---Reflection tools---Reflection file editor. The space group used was P222. Then, I used the Phenix---Molecular replacement to find a solution (try all possible in same pointgroup), and the MR solution was in space group P212121. And then, I reindexed the data in XDS using space group P212121 and then generate the mtz file in space group P212121. So, I have two mtz file, in space group P212121 and P222. When I refine the MR solution with the different mtz files, the map generated is not same for the ligand. The statisitcs is better with P222 mtz file than P212121 mtz file. I am wondering why the density for the ligand and the statistics is different using mtz file in different space groups and which mtz file should I use to get the final structure model. Thank you so much! Best, Wei

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phenix.refine and R free values
by PC 03 Sep '14

03 Sep '14

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OMIT map
by abhishek jamwal 02 Sep '14

02 Sep '14

Dear phenixbb members, I want to build a SA-OMIT map for a ligand present in xtal structure of a protein. I am using "AutoBuild-create omit map" module of PHENIX ver. 1.8.4-1496 (graphical interface) for this purpose. However, when I run the program after adding requisite input files, it gives an error: " The map file parameter is not supported for omit map calculation" Q: What is this "file parameter" and way to fix this error/parameter ? waiting for answers many thanks in advance Abhishek Jamwal Structural Biology Group ICGEB, New Delhi

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Phasing using CryoEM Map
by Alexander Kintzer 02 Sep '14

02 Sep '14

Hello All, I trying to phase my 4Å data with low resolution cryoEM maps (various 12-18Å). There is some documentation, but not really for dealing with EM data. I am having trouble converting the EM data from mrc to suitable F's for phaser. One would want to try different density contours of the cryoEM map, but I haven't found a good way to accomplish this. I also have been unable to search for Ta6Br12 clusters using Autosol even though the documentation seems to suggest that it is possible using the "TX" or "XX" designation for heavy atom search. Any guidance would be extremely helpful. best, Alex

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Tau angles
by George Devaniranjan 02 Sep '14

02 Sep '14

Hi, Is there a way of extracting the tau (and omega) angles of residues in phenix ? Thank you

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Re: [phenixbb] following on the anomalous map
by Kay Diederichs 29 Aug '14

29 Aug '14

Hi Charles, > Date: Thu, 28 Aug 2014 09:59:30 -0400 > From: CPMAS Chen <cpmasmit(a)gmail.com> > To: Gabor Bunkoczi <gb360(a)cam.ac.uk> > Cc: "PHENIX user mailing list \(phenixbb(a)phenix-online.org\)" > <phenixbb(a)phenix-online.org> > Subject: Re: [phenixbb] following on the anomalous map > Message-ID: > <CAAU4GKbzA37j=51X4jMOJjq3t4rKW7Jz9+CQrPxO-HN1kFOOiQ(a)mail.gmail.com> > Content-Type: text/plain; charset="utf-8" > > HI, Gabor, > > Thanks for you suggestion. > > I tried this method, it did not give out NO sites for Br. > > why there is apparent anomalous signal and I cannot identify any Br sites? are you sure that your data processing used the correct parameters? E.g. in XDS you should definitively be using "FRIEDEL'S_LAW=FALSE". If you use XSCALE after XDS, it automagically picks up this setting from XDS_ASCII.HKL i.e. you don't have to specify this again. If you, by mistake, use FRIEDEL'S_LAW=TRUE, then the large intensity differences of Friedel pairs will be judged as outliers by XDS, and these reflections will be rejected - that might lead to featureless maps. If the anomalous signal is very strong, and the multiplicity is high, and the Chi^2 values are >1.5, you may also want to use (additionally) "STRICT_ABSORPTION_CORRECTION=TRUE" . But this is rarely necessary. There are similar options in other data processing programs. If you mix and match data processing programs (e.g. XDS integration and aimless scaling) you have to be careful to have the right settings in all programs. best, Kay > > As Nat pointed out, other atoms should have very weak anomalous signal > diffracted at Br absorption peak (3.8e- for Br, versus 0.2e- for the > sulfurs). In the difference map, I can clearly see some peaks at high sigma > (> 6), but the anomalous difference map(they are all generated by > phenix.refine or phenix.maps) is almost featureless, or the peaks has > no overlaps. The anomalous difference gives the possible place of Br while > the difference map gives the possible place of the whole ligand, and I > assume there should be some overlaps between them. Am I right? > > Charles >

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Re: [phenixbb] following on the anomalous map
by CPMAS Chen 29 Aug '14

29 Aug '14

HI, Gabor, Thanks for you suggestion. I tried this method, it did not give out NO sites for Br. why there is apparent anomalous signal and I cannot identify any Br sites? As Nat pointed out, other atoms should have very weak anomalous signal diffracted at Br absorption peak (3.8e- for Br, versus 0.2e- for the sulfurs). In the difference map, I can clearly see some peaks at high sigma (> 6), but the anomalous difference map(they are all generated by phenix.refine or phenix.maps) is almost featureless, or the peaks has no overlaps. The anomalous difference gives the possible place of Br while the difference map gives the possible place of the whole ligand, and I assume there should be some overlaps between them. Am I right? Charles On Wed, Aug 27, 2014 at 6:28 AM, Gabor Bunkoczi <gb360(a)cam.ac.uk> wrote: > Hi Charles, > > I could be totally misunderstanding what you are trying to achieve, but I > think what you need to do is an MR-SAD calculation. First, solve the > structure with MR (use the macromolecule from the non-Br structure, or use > your current model if you have done refinement on it), and use the > Phaser-EP GUI, and select "SAD starting from MR model". This should > highlight any Br you may have, and gives you a PDB-file with all the peaks > (you can also get a proper anomalous map, but this is only useful for > visualization - the peak search will identify any peaks you may have). > > Let me know if you need more details! > > BW, Gabor > > > On 2014-08-26 14:49, CPMAS Chen wrote: > >> Thanks. Nat. >> >> Since I have some MET and CYT in the protein, could I try to supply >> their sulfur as the initial anomalous scatters? >> >> As for the anomalous isomorphous difference map, would it be useful I >> compare the datasets acquired at 1A wavelength and at the Br >> absorption peak (~0.92A)? >> >> Appreciate your help >> >> Charles >> >> On Mon, Aug 25, 2014 at 5:08 PM, Nathaniel Echols <nechols(a)lbl.gov> >> wrote: >> >> On Sun, Aug 24, 2014 at 6:46 AM, CPMAS Chen <cpmasmit(a)gmail.com> >>> wrote: >>> >>> Here is the point I am not clear. If I am using phenix.refine to >>>> generate LLG map, how do I pick the anomalous group since I have >>>> not placed them in the model yet? >>>> >>> >>> You can't. The LLG map only becomes really useful once you have >>> some anomalous scatterers placed and refined - this is how Phaser >>> substructure completion works. If your molecules have no other >>> significant anomalous scatterers other than the expected Br, the LLG >>> map won't do you much good. >>> >>> By the way, when I choose ion_placement and specify Br, the result >>>> comes with no Br. >>>> >>> >>> Not too surprising, since the code is tuned to look for ions, not >>> part of a covalent molecule, and halides also tend to bond >>> non-specifically and we haven't figured out how to deal with that >>> yet. >>> >>> I want to find whether the Br-containing ligand is seen in my >>>> protein which I have a high resolution structure available. >>>> >>>> I have data collected at Br wavelength, peak or higher position. >>>> Phenix.xtriage reported that the anomalous signal is present to >>>> about 4A. However, both AutoSol or MR-SAD cannot identify the Br >>>> position. Simply say, AutoSol or MR-SAD can not generate any >>>> solution. Well, of course, the simple answer would be that there >>>> is no such ligand cocrystallized. >>>> >>> >>> The simplest explanation is that you just don't have enough >>> anomalous signal to determine the substructure, which can be true >>> even if your ligand is bound. Running experimental phasing to >>> figure this out is unnecessary and time-consuming. >>> >>> Anyway, I am trying to see if the anomalous difference map or >>>> LLG(generated by phenix.maps, this would be the initial one I >>>> assume) can tell me anything more useful. >>>> >>>> So, my question on this topic would be what is a better way you >>>> guys would recommend to identify these Br-ligands? By the way, I >>>> did have the native datasets for the same protein with ligand. >>>> >>> >>> I think in this case I would start with the simple anomalous >>> difference map. If you run phenix.find_peaks_holes (it's in the >>> GUI, of course) and give anomalous data as input, it can pick out >>> the highest peaks in the anomalous map. If the ligand really is >>> bound and the Br site is ordered I would expect this to be >>> detectable. Another alternative is to compute an anomalous >>> isomorphous difference map between a dataset collected at or above >>> (in eV) the Br peak, and a dataset collected below the peak. This >>> will allow you to visualize the wavelength-dependent difference in >>> anomalous scattering, and it's going to be specific for elements >>> with absorption edges within that energy range. But I really don't >>> think this should be necessary to answer your question. >>> >>> -Nat >>> >> >> -- >> >> *************************************************** >> >> Charles Chen >> >> Research Associate >> >> University of Pittsburgh School of Medicine >> >> Department of Anesthesiology >> >> ****************************************************** >> >> >> _______________________________________________ >> phenixbb mailing list >> phenixbb(a)phenix-online.org >> http://phenix-online.org/mailman/listinfo/phenixbb >> > > -- > ################################################## > > Dr Gabor Bunkoczi > > Cambridge Institute for Medical Research > Wellcome Trust/MRC Building > Addenbrooke's Hospital > Hills Road > Cambridge CB2 0XY > ################################################## > -- *************************************************** Charles Chen Research Associate University of Pittsburgh School of Medicine Department of Anesthesiology ******************************************************

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How to tighten ligand geometry in phenix.refine?
by Blankenfeldt, Wulf 28 Aug '14

28 Aug '14

Dear all, I am currently trying to refine a cacodylate ion that partially occupies the phosphate binding site of a PLP cofactor – partially meaning ~90%, in fact I am leaving the PLP out altogether. When I am refining this in phenix. refine, the cacodylate becomes “ugly”: the tetraeder gets slightly squashed and the atoms are flying apart a bit such that they are not automatically connected in Coot any more. I am now wondering if I can tighten the geometry just for the cacodylate to prevent this from happening, either by sending a magical command or by fiddling with the dictionary. Can anyone advise me, please? Regards, Wulf ________________________________ Helmholtz-Zentrum für Infektionsforschung GmbH | Inhoffenstraße 7 | 38124 Braunschweig | www.helmholtz-hzi.de Das HZI ist seit 2007 zertifiziertes Mitglied im "audit berufundfamilie" Vorsitzende des Aufsichtsrates: MinDir’in Bärbel Brumme-Bothe, Bundesministerium für Bildung und Forschung Stellvertreter: MinDirig Rüdiger Eichel, Niedersächsisches Ministerium für Wissenschaft und Kultur Geschäftsführung: Prof. Dr. Dirk Heinz; Franziska Broer Gesellschaft mit beschränkter Haftung (GmbH) Sitz der Gesellschaft: Braunschweig Handelsregister: Amtsgericht Braunschweig, HRB 477

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