- phenixbb - phenix-online.org

DNA sugar pucker
by Laura Murray 26 Oct '08

26 Oct '08

Hi. I'm one of the Richardsons' people. I have more experience with RNA, but have looked at DNA some as well. 1. On C2'-endo and C3'-exo being equivalent: no, not quite equivalent, but related. If you do have C1', C4', and O4' in the plane, then "popping" C2' out on one side or C3' out on the other is relatively similar (sort of) and there's a recognized "twist" conformation where you've got them both out of plane a bit. However, you can really get C3' mostly in-plane with the other three and have a conformation that's distinctly a C2' endo pucker rather than looking like it could be either one. If you're building ideal B-form DNA, it would be better to use a real C2'-endo pucker than the twist, and certainly better than using the C3'-exo. 2. I'm afraid I don't know the appropriate format for use with PHENIX, but there are pucker-specific parameters available on the Nucleic Acid Database site: http://ndbserver.rutgers.edu -- specifically, here: http://ndbserver.rutgers.edu/standards/parameter.html -- these are set up for XPLOR, but the values should help. At any rate, these files distinguish the dihedrals for C2'-endo and C3'-endo sugar puckers. (The set for higher resolution also provides slightly different bond lengths and angles for them, since the ring strains are a bit different.) And I don't think they make a habit of turning up C3'-exo. Laura Murray

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sugar puckering in an ideal B-DNA
by chern 26 Oct '08

26 Oct '08

Hi all, does anybody know why coot and sybil (and may be others that I don't know about) generate an ideal dna with C3*-exo puckers instead of C2*-endo, as text books say. maia

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phenix.refine output map format
by Paul Emsley 25 Oct '08

25 Oct '08

Dear Phenixers, Is is possible for phenix.refine to output a ccp4 map? If so, how? Thanks, Paul.

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elbow
by chern 24 Oct '08

24 Oct '08

Dear all, could I use eLBOW to create a .cif file for a B-DNA to restrain sugar puckers? Maia

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sugar puckering in DNA
by Maia Cherney 24 Oct '08

24 Oct '08

Hi Yu Seon. I would appreciate it very much if you send me your added restraints to the cif file. Maia YS. Chung wrote: > Hi Maia, > I had the same problem when I was refining with phenix. I ended up > looking at the torsions that were used in 3DNA (the program I used to > analyze the puckerings) and manually added the restraints to the .cif > files used in phenix. I can send you an example if you'd like. The > puckerings improved a lot when I used the modified .cif files. > Yu Seon > > On Fri, 24 Oct 2008 10:43:44 -0600 > "chern" <chern(a)ualberta.ca> wrote: > >> Sorry, I gave a wrong subject name in my previous e-mails. Should've >> been sugar puckering in DNA. >> I am wondering why the default .cif file for DNA does not include all >> >> information about sugar puckers. >> I do not have some fancy nucleotides. They are regular. >> >> Maia >> >> ----- Original Message ----- From: "Ralf W. Grosse-Kunstleve" >> <rwgk(a)cci.lbl.gov> >> To: <phenixbb(a)phenix-online.org> >> Sent: Friday, October 24, 2008 10:03 AM >> Subject: Re: [phenixbb] elbow >> >> >> >>>> The answer is yes but there may be better options. Ralf is the >>>> >> best >> >>>> person to answer this question but one option is to start with the >>>> >> .cif >> >>>> file in the monomer library. >>>> >>> This is more a chemistry question than a formatting question. >>> Since I'm not deeply familiar with the DNA chemistry, I was >>> >> pointing >> >>> Maia to phenixbb in hopes that someone may already have figured out >>> the list of torsion angle restraints to fix sugar puckers. >>> >>> What Maia really wants is: >>> >>> >>>> could you please send me a specific example of how to modify a cif >>>> >> file >> >>>> to specify the sugar puckers in DNA (I want them C2'-endo). >>>> >>> Has anyone on this list done this already? >>> >>> Ralf >>> _______________________________________________ >>> phenixbb mailing list >>> phenixbb(a)phenix-online.org >>> http://www.phenix-online.org/mailman/listinfo/phenixbb >>> >>> >> _______________________________________________ >> phenixbb mailing list >> phenixbb(a)phenix-online.org >> http://www.phenix-online.org/mailman/listinfo/phenixbb >> > >

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Re: [phenixbb] phenix.autobuild
by Matthew Chu 24 Oct '08

24 Oct '08

Thank you for the detailed information Tom, my autobuild job is actually running properly! Just some more minors questions: 1. AutoBuild Wizard will use phenix.elbow to generate geometries for any ligands that are not recognized, but how can I find out which ligands that can actually be recognized by phenix? Or to be save, we better run elbow to generate the libraries for every single ligands? 2. eLBOW can automatically add hydrogens to the input molecules if there are less than a quarter of the possible hydrogens, however this command doesn't work: phenix.elbow input_file.pdb --add-hydrogens=True, and I can't find this option under the elbow manual? And actually I would like to remove those hydrogens so it should be "add-hydrogens=false"? I am now using phenix-1.3-rc2. Thanks again! Matt -- ---------------------------------------------------------------------------- Matthew LH Chu PhD Student School of Pharmacy and Pharmaceutical Sciences University of Manchester ----------------------------------------------------------------------------

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NAG-ASN link geometry
by nihmayerm 23 Oct '08

23 Oct '08

We are refining a 2.7 A structure with multiple ASN-NAG links using phenix-1.3-final. The torsion angle between the Asn amide and the sugar is quite variable, while from the chemistry of this link we would expect a value close to 180°, as reported in the PDB survey by Imberty & Perez (Protein Engineering 8:669-709). A quick look at some entries in the PDB revealed close to textbook geometry for the NAG-ASN link in structures around 1Å resolution (e.g. 1UWC) and gets much worse in some lower resolution structures, including those refined with PHENIX. The NAG-ASN link used by PHENIX does not contain a torsion angle definition, and I would like to ask (i) if its appropriate to use one in refinement, and if so (2) could people share their cif file for this link. Thanks - MLM

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optimize weights error
by Sean Johnson 23 Oct '08

23 Oct '08

I just tried optimizing weights in phenix.refine using optimize_wxc=true and optimize_wxu=true in the command line. I got the following error: ----------xray term weight optimization (wxc)---------- Traceback (most recent call last): File "/usr/local/phenix-1.3b-rc5/phenix/phenix/command_line/refine.py", line 5, in <module> command_line.run(command_name="phenix.refine", args=sys.argv[1:]) File "/usr/local/phenix-1.3b-rc5/phenix/phenix/refinement/command_line.py", line 82, in run call_back_after_monitor_collect=call_back_after_monitor_collect) File "/usr/local/phenix-1.3b-rc5/phenix/phenix/refinement/driver.py", line 1150, in run call_back_after_monitor_collect = call_back_after_monitor_collect) File "/usr/local/phenix-1.3b-rc5/phenix/phenix/refinement/strategies.py", line 446, in refinement_machine log = log) File "/usr/local/phenix-1.3b-rc5/phenix/phenix/refinement/weight_xray_chem.py", line 252, in __init__ self.wxc_optimization() File "/usr/local/phenix-1.3b-rc5/phenix/phenix/refinement/weight_xray_chem.py", line 507, in wxc_optimization wxc = self.holder.wxc AttributeError: weight instance has no attribute 'holder' Any suggestions? Thanks, Sean -- Sean Johnson, PhD R. Gaurth Hansen Assistant Professor Utah State University Department of Chemistry and Biochemistry 0300 Old Main Hill Logan, UT 84322-0300 (435) 797-2089 (435) 797-3390 (fax) sean.johnson(a)usu.edu

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phenix.autobuild
by Matthew Chu 22 Oct '08

22 Oct '08

Dear all, I tried to rebuild my structure from a refined model (by refmac) by phenix.autobuild. I am not sure if it runs properly since this is my first time to run this module....it took like almost a day to just finish the run_1 (there should be five runs by default?), which means it will take me another 4 days to finish the whole thing. My protein has around 350 residues and in the refined model, I have omitted some loops (about 80 residues) because I cannot see the electron density of those regions. I have put the seq.dat file with the full sequence (~350 residues) and the commands "place_water=Yes" and "s_annealing=True". The resolution is 2.4 A. Should it be taken so long to run? Thanks in advance! Kind regards, Matt -- ---------------------------------------------------------------------------- Matthew LH Chu PhD Student School of Pharmacy and Pharmaceutical Sciences University of Manchester ----------------------------------------------------------------------------

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phenix.pdbtools question
by Simon Kolstoe 21 Oct '08

21 Oct '08

Dear phenix list, I am wanting to model a poly-proline structure. I created the file in PyMOL, saved it as a pdb, and then tried to regularize it with: phenix.pdbtools polypro.pdb --geometry_regularization However the program reported (snipped to the last few lines): ATOM 63 CD PRO 6 -3.290 3.487 -2.968 1.00 0.00 C ATOM 69 2HD PRO 6 -2.824 2.626 -3.453 1.00 0.00 H Distance model: 1.09209 (ideal: 0.97) ATOM 63 CD PRO 6 -3.290 3.487 -2.968 1.00 0.00 C ATOM 70 3HD PRO 6 -4.165 3.171 -2.396 1.00 0.00 H Distance model: 1.44721 (ideal: 1.473) ATOM 57 N PRO 6 -2.321 4.145 -2.118 1.00 0.00 N ATOM 63 CD PRO 6 -3.290 3.487 -2.968 1.00 0.00 C Distance model: 1.53855 (ideal: 1.525) ATOM 58 CA PRO 6 -1.810 5.407 -2.632 1.00 0.00 C ATOM 59 C PRO 6 -2.332 6.603 -1.817 1.00 0.00 C Distance model: 1.23088 (ideal: 1.231) ATOM 59 C PRO 6 -2.332 6.603 -1.817 1.00 0.00 C ATOM 60 O PRO 6 -3.080 6.424 -0.856 1.00 0.00 O Sorry: Number of bonds with excessive lengths: 74 I thought the whole purpose of geometry regularization was to get rid of excessive lengths, not just tell me they are there!! How do I get the program to really regularize my geometry? Thanks, Simon

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phenix.reduce (v1.3) changes
by Mark Collins 21 Oct '08

21 Oct '08

Hi Did the --ALLALT command change. I thought the --help gave the flag description as "builds hydrogens for all conformations" but no it says "process adjustments for all conformations" And by default (-ONLYA) so I only have conf A with hydrogens using the --ALLALT flag. Long and short of it I think something is up? Thanks Mark

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postdoc position in LBNL
by Peter Zwart 21 Oct '08

21 Oct '08

Dear All, We would like to bring the following postdoctoral research position to your attention. Within Lawrence Berkeley Laboratory, we have an opening for a postdoc to work on the development of new software for the analysis of small angle X-ray scattering (SAXS) data. The availability of user friendly, robust software analysis tools for SAXS data is of growing importance as the biological community is increasingly using SAXS as a standard method to analyze complex biological systems. We are developing a new set of tools, including a software library, for SAXS data analysis. The successful candidate will have the opportunity to work with experienced software developers in the field of biophysics and interact with users and beamline staff on SAXS beamline 7.3.3 at the Advanced Light Source (ALS) in Berkeley California. Interested candidates can contact me (Peter Zwart, PHZwart(a)lbl.gov) for more details, or visit the LBL job site at: http://jobs.lbl.gov/ Sincerely, Peter Zwart -- ----------------------------------------------------------------- P.H. Zwart Beamline Scientist Berkeley Center for Structural Biology Lawrence Berkeley National Laboratories 1 Cyclotron Road, Berkeley, CA-94703, USA Cell: 510 289 9246 BCSB: http://bcsb.als.lbl.gov PHENIX: http://www.phenix-online.org CCTBX: http://cctbx.sf.net -----------------------------------------------------------------

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Twin refinement with anomalous pairs
by Francis E Reyes 21 Oct '08

21 Oct '08

All How does phenix.refine handle the twin refinement target when refining against F+/F-? I'm specifically asking for the proper assignment of F +/F- for twin related reflections (e.g. 10.1107/S0907444902021704). My data is currently in P41 with friedel pairs as output by scala. Thanks FR --------------------------------------------- Francis Reyes M.Sc. 215 UCB University of Colorado at Boulder gpg --keyserver pgp.mit.edu --recv-keys 67BA8D5D 8AE2 F2F4 90F7 9640 28BC 686F 78FD 6669 67BA 8D5D

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Re: [phenixbb] sa_omit-map
by mathieu Coincon 19 Oct '08

19 Oct '08

Hi, omit-map works fine for me but I have two items on my wish list. 1) Can we compute a difference-map (mFo-DFc map instead of 2mFo-DFc map) ? 2) Is it possible to play with the size of the area omitted around the selection ? Thanks again. A true phenix-fan -------------- Mathieu Coincon PhD Student Universite de Montreal Biochemistry 514-343-6111 #5352

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phenix.refine: including modifications
by Patrick Loll 17 Oct '08

17 Oct '08

Hi all, I'm starting to use phenix.refine and have some questions about defining modifications during refinement: I want to refine a structure that includes several alpha-D-mannose residues. I see that mon_lib_list.cif contains, under the "LIST OF RECOGNIZED MODIFIED MONOMERS," the following line: MAN-a-D MAN-b-D SUG-a-D MAN alpha_D_mannose D-pyranose Question: Where/how do I invoke this modification? I.e., how do I tell the refinement program that a particular sugar is an alpha, and not a beta, mannose? Clearly I can't label the residue MAN-a-D in the PDB file, as this would step on the chain identifier. I'm guessing that I label each sugar MAN in the PDB file, and then insert some instructions about applying the modification in the CIF file that I supply to the refinement program. However, I'm not able to find an example of the appropriate syntax. Thanks, Pat Loll ------------------------------------------------------------------------ --------------- Patrick J. Loll, Ph. D. Professor of Biochemistry & Molecular Biology Director, Biochemistry Graduate Program Drexel University College of Medicine Room 10-102 New College Building 245 N. 15th St., Mailstop 497 Philadelphia, PA 19102-1192 USA (215) 762-7706 pat.loll(a)drexelmed.edu

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Hydrogen occupancy issue?
by Mischa Machius 17 Oct '08

17 Oct '08

Hi - I have a problem regarding occupancies of hydrogens in residues with alternate conformations. Specifically, when a residue exists in alternate conformations, the H hydrogen of the following residue (the one attached to the N) also exists in the same number of alternate locations. The occupancies of these hydrogens do not add up to 1.00 like the occupancies of the hydrogens for the preceding residue do. In fact, these occupancies are all 1.00. Is that a bug, a feature, or did I commit a user error somehow? Example: ... ATOM 956 H AHIS A 293 6.967 -36.722 8.227 1.00 15.31 H ATOM 957 H BHIS A 293 6.913 -36.667 8.216 1.00 15.31 H ATOM 958 H CHIS A 293 6.888 -36.648 8.202 1.00 15.31 H ... The preceding Ser A 292 exists in three alternate conformations with occupancies A=0.53, B=0.18, C=0.29; sum = 1.00 The corresponding hydrogens have occupancies A=0.52, B=0.19, C=0.29; sum = 1.00 (I can accept that they have somewhat different occupancies than the attached heavy atoms, based on a previous thread about this issue, although the discrepancies are now much smaller in the 1.3- final version compared to 1.3-rc2) The H hydrogens of the following residue (His A 293) have occupancies A=1.00, B=1.00, C=1.00; sum = 3.00, and the RCSB starts yelling. Should I just manually edit the values and set them to the occupancies of the hydrogens in the preceding residue? Any help appreciated. Thanks so much. Best - MM -------------------------------------------------------------------------------- Mischa Machius, PhD Associate Professor Department of Biochemistry UT Southwestern Medical Center at Dallas 5323 Harry Hines Blvd.; ND10.214A Dallas, TX 75390-8816; U.S.A. Tel: +1 214 645 6381 Fax: +1 214 645 6353

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Weighted phase combination in phenix.refine?
by Francis E Reyes 17 Oct '08

17 Oct '08

Hi all I have experimental phases and a preliminary model. Will phenix.refine do phase combination while weighting the experimental phase and model phases (which also has NCS) ? By default? Thanks FR --------------------------------------------- Francis Reyes M.Sc. 215 UCB University of Colorado at Boulder gpg --keyserver pgp.mit.edu --recv-keys 67BA8D5D 8AE2 F2F4 90F7 9640 28BC 686F 78FD 6669 67BA 8D5D

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high temperature factor refinement
by allbette＠gmail.com 17 Oct '08

17 Oct '08

Hi All, I just refined a structure at 2.95A and getting a good R-work and R-free(0.236 and 0.274). When I checked the PDB, I found many residues have high temperature factor over 100. How can I use Phenix or CNS fix those high temperature factor for further refinment? Thank you Jason

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Re: [phenixbb] sa_omit-map -- it's fine
by Thomas C. Terwilliger 17 Oct '08

17 Oct '08

Hi again Pavel and Vladimir, The omit maps are fine. I'm sorry for the false alarm; I had run a tiny test structure with too few omit boxes so that the omitted regions were way too much of the structure and it looked really bad. Using more omit regions fixed the problem. A regular structure (nsf-d2 from the PHENIX structure library) gets a fine sa-omit map with the defaults. A further-improved map can be obtained with a higher-than-default value of "n_box_target=32" (default=12, note that you don't necessarily get exactly the number you ask for as it has to be something that the asymmetric unit can be divided into.) All the best, Tom T Hi Pavel and Vladimir, After all this discussion...I think there is something wrong with the composite omit maps in the current version. They do not finish correctly...I will check this out. If you instead just omit around the atoms in a pdb file with "omit_box_pdb=target.pdb" that seems fine however. I'm sorry for the problem. All the best, Tom T > Hi Tom, > > don't we need to add "maps_only=True" as well (as Manual suggests in section "Just make maps; don't do any building."; > http://www.phenix-online.org/documentation/autobuild.htm) ? > > I'm asking because the original question was specific about it: compute map and "nothing extra". > > Thanks, > Pavel. > > On 10/13/2008 2:17 PM, Thomas C. Terwilliger wrote: >> Hi Vladimir, >> You can do this with: >> >> phenix.autobuild data=data.mtz model=coords.pdb >> composite_omit_type=sa_omit nproc=4 >> >> All the best, >> Tom T >> >> >> >>> After phenix.refine stage I would like to get just the sa_omit map for the >>> whole assymetric unit (nothing extra). How can I do it? >>> Regards. >>> Vladimir >>> >>> >>> >>> _______________________________________________ >>> phenixbb mailing list >>> phenixbb(a)phenix-online.org >>> http://www.phenix-online.org/mailman/listinfo/phenixbb >>> >>> >> >> _______________________________________________ >> phenixbb mailing list >> phenixbb(a)phenix-online.org >> http://www.phenix-online.org/mailman/listinfo/phenixbb >> >

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sa_omit-map
by pletnev＠hwi.buffalo.edu 17 Oct '08

17 Oct '08

After phenix.refine stage I would like to get just the sa_omit map for the whole assymetric unit (nothing extra). How can I do it? Regards. Vladimir

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Reporting phasing statistics.
by Francis E Reyes 15 Oct '08

15 Oct '08

So normally when I run autosol, my primary indicator of 'goodness' would be the SKEW, but in reporting to papers, it seems that the MIR statistics involve Rcullis, phasing power, and FOM. I can find FOM from solve_x.prt and resolve_x.log but where are the others? Thanks FR --------------------------------------------- Francis Reyes M.Sc. 215 UCB University of Colorado at Boulder gpg --keyserver pgp.mit.edu --recv-keys 67BA8D5D 8AE2 F2F4 90F7 9640 28BC 686F 78FD 6669 67BA 8D5D

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? about optimize weights
by gerwald jogl 15 Oct '08

15 Oct '08

Hi All, I just started using phenix.refine and it's working quite well so far. I ran the optimize weight strategy at the end of a test refinement and it lowered the Rfree as intended. Unfortunately, when I ran the next refine job based on the output .def file, it seems that the 'best weights' found in the previous run were not conserved as the geometry and R factors got a lot worse. Where can I find the weights determined by the optimize run and how can I fix those for further refinement? Thanks, Gerwald

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helix deformed during refinement in phenix
by Raja Dey 13 Oct '08

13 Oct '08

Dear All, I am using phenix to refine a long helix of about 120 residues in a complex structure, but in course of refinement the helix becoming distorted from helical geometry. As a result when I am displaying the refined structure in pymol as cartoon one long helix showed 3/4 discontinuous helices in a single chain. Is there any way to constrain or restrain the helix during refinement, so that refinement process can maintain the helical geometry? Any suggestion is well appreciated. With regards... Raja Raja Dey, Ph.D. Research Associate Molecular and Computational Biology University of Southern California

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detwin data
by HUA YUAN 13 Oct '08

13 Oct '08

Dear Phenix community, I've used the phenix.refine with its detwin function. Is there any way to have a detwinned data output so that I can use it for other things. I tried use CCP4 detwin with the same twin law and twin fraction obtained from Phenix. However, this didn't work. Another question is whether I can use "some" phase information, say from DM into Phenix? I tried to include the PHIDM but Phenix complained about it saying "wrong array". Any suggestions or comments are hightly appreciated! Thanks, Hua

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Re: [phenixbb] Files generated in Autobuild from simulated annealing runs
by Tom Terwilliger 07 Oct '08

07 Oct '08

Hi Rebecca, I'm sorry this didn't get answered on the phenix_bb! I somehow missed it too. When you run an omit map with model=mymodel.pdb omit_box_pdb=mymodel.pdb omit_res_start_list=500 omit_res_end_list=500 the autobuild wizard edits mymodel.pdb, setting the occupancies of all atoms that are within a box enclosing the atoms in residue 500 of mymodel.pdb (plus a 2 A border) to zero. Then it runs the cycles of autobuild you specify (in this case just a SA step), and produces a density-modified map (resolve_composite_map.mtz) using the resulting model to generate phase information (and keeping the occupancies of these atoms at zero). If mydata.mtz contains phase information, that is used as well. The output map is in resolve_composite_map.mtz and a pseudo-map showing where the OMIT region(s) is(are) located is in omit_region.mtz The file overall_best_denmod_map_coeff.mtz is actually not really relevant or useful when you are doing OMIT maps because it is just one of the intermediate files that are produced. In this particular example it will be identical to resolve_composite_map.mtz but if you do other types of OMIT maps it won't be the same. I changed the output of the autobuild wizard recently, so you might want to upgrade to the 1.3-final version. The end of the log file in this case should say: -------------------------------------------------- Summary of model-building for run 1 Tue Oct 7 08:17:30 2008 Files are in the directory: /net/chevy/raid1/terwill/misc/test/ AutoBuild_run_1_/ Starting mtz file: /net/chevy/raid1/terwill/misc/test/perfect.mtz Sequence file: /net/chevy/raid1/terwill/misc/test/seq.dat Composite omit map is in : /net/chevy/raid1/terwill/misc/test/ AutoBuild_run_1_/OMIT/resolve_composite_map.mtz Boundaries of omit regions are in : /net/chevy/raid1/terwill/misc/test/ AutoBuild_run_1_/OMIT/omit_region.mtz -------------------------------------------------- Which I hope is clearer than earlier output in which the overall_best_denmod_map_coeff.mtz file is mentioned but is irrelevant. I hope that helps! All the best, Tom T On Oct 7, 2008, at 7:19 AM, Page, Rebecca wrote: > Hi Tom, > I posted the question on the phenix bb and, when I got no response, > shot an email over to Frank von Delft, an old friend, to see if he > knew answer. > > He didn’t, but recommended I email you directly and to “ask him to > post the answer on the general bb :)”. He also mentioned he hadn’t > seen the post on the phenix bb and I would be interested to know if > you did not see it either (I received it). > > At any rate, here it goes: > > > I am newcomer to phenix and have a rookie question about the > generated > > files using the phenix.autobuild command. I generated an sa-omit map > > of my model, omitting the coordinates for a bound ligand (ligand is > > residue > > 500): > > > > phenix.autobuild data=mydata.mtz model=mymodel.pdb > > omit_box_pdb=mymodel.pdb omit_res_start_list=500 > omit_res_end_list=500 > > omit_chain_list=A composite_omit_type=sa_omit > > > > The output omit map (resolve_composite_map.mtz) looks great. > > > > > > My question is: > > What, exactly, is the "overall_best_denmod_map_coeff.mtz" in this > case > > and how is it related, if at all, to the > "resolve_composite_map.mtz"? > > > Thanks for your help, > Rebecca > > Rebecca Page > Brown University >

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