- phenixbb - phenix-online.org

restrains for nucleaic acid base pairs
by Imre Toeroe 08 Apr '09

08 Apr '09

Hi, Does anybody know an easy way to restrain nucleic acid base pairs (base stacking+Watson-Crick base pairing) in phenix.refine? I am refining against a 3.3 A dataset. Thanks, Imre

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phenix autobuild and omit map
by rpai＠berkeley.edu 07 Apr '09

07 Apr '09

Hi, I have a loop that was improperly built when I ran autobuild. the density according to the Fobs-Fcalc maps is not that great. Someone told me that autobuild can use omit maps to build / rebuild the loops so you dont have to do it by hand. Looking at the manual, I found the command, but am a little confused. The model used is the entire model correct? the target.pdb is the chain or region that was not correctly built. For iterative building...how many cycles should I go for? phenix.autobuild data=w1.sca model=coords.pdb omit_box_pdb=target.pdb \ composite_omit_type=iterative_build_omit thanks Raj

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imaginary map (anomlous difference Fourier) from phenix
by Ulrich Baumann 06 Apr '09

06 Apr '09

Hi everybody, I used phenix for calculating anomalous Fourier coefficients (script below) and I get the desired file containing columns FANOM PHANOM. When I read this into Coot for displaying the imaginary map, I only get noise, regardless of resolution cutoff etc. When I export the Fcalcs as CNS format and use CNS for the map calculation, I get very high peaks (i.e. excellent signal-to-noise ratio) on the anomalous scatterers. Inspection of the phenix fcalc file reveals that FOFCWT_no_fill equals FANOM and PHFOFCWT_no_fill is identical to PHANOM . Obviously I am doing something stupidly wrong. Setting xray_data.force_anomalous_flag_to_be_equal_to=true doesn't change anything, by the way, and i am using the latest Phenix version. I vaguely remember that there were an issue with anomlous data but can't find the thread. Thank you very much in advance for enlightening me, Ulrich # source /usr/local/phenix-1.4-3/phenix_env phenix.refine m226h1_rfree-unique.mtz m226h1_hkl2000_6_waters_001.pdb main.number_of_macro_cycles=1 \ refinement.input.xray_data.labels="F(+),SIGF(+),F(-),SIGF(-)" \ xray_data.high_resolution =3.5 strategy=none export_final_f_model=cns output.prefix=sfcalc --overwrite * Space group = 'P3121' (number 152) The mapcoeff.mtz looks like OVERALL FILE STATISTICS for resolution range 0.000 - 0.319 ======================= Col Sort Min Max Num % Mean Mean Resolution Type Column num order Missing complete abs. Low High label 1 ASC 0 49 0 100.00 23.7 23.7 88.43 1.77 H H 2 NONE 0 28 0 100.00 8.4 8.4 88.43 1.77 H K 3 NONE -69 69 0 100.00 0.6 26.2 88.43 1.77 H L 4 NONE 0.0 2220.8 0 100.00 235.55 235.55 88.43 1.77 F 2FOFCWT 5 NONE -180.0 180.0 0 100.00 2.65 89.99 88.43 1.77 P PH2FOFCWT 6 NONE 0.0 956.4 0 100.00 72.48 72.48 88.43 1.77 F FOFCWT 7 NONE -180.0 180.0 0 100.00 2.16 89.97 88.43 1.77 P PHFOFCWT 8 NONE 0.0 2202.8 117 99.84 234.51 234.51 37.16 1.77 F 2FOFCWT_no_fill 9 NONE -180.0 180.0 117 99.84 2.78 89.99 37.16 1.77 P PH2FOFCWT_no_fill 10 NONE 0.0 961.2 117 99.84 72.39 72.39 37.16 1.77 F FOFCWT_no_fill 11 NONE -180.0 180.0 117 99.84 2.19 89.95 37.16 1.77 P PHFOFCWT_no_fill 12 NONE 0.0 961.2 117 99.84 72.39 72.39 37.16 1.77 F ANOM 13 NONE -180.0 180.0 117 99.84 2.19 89.95 37.16 1.77 P PHANOM No. of reflections used in FILE STATISTICS 72570 1 1 3 88.81 -133.90 400.50 -133.90 139.90 -134.31 502.82 -134.31 502.82 -134.31 1 1 4 719.55 109.38 336.98 109.38 703.51 104.61 304.13 104.61 304.13 104.61 1 1 5 987.30 124.20 664.11 124.20 985.68 119.49 659.96 119.49 659.96 119.49 1 1 6 871.35 35.76 152.79 35.76 894.80 36.84 198.58 36.84 198.58 36.84 1 1 7 425.64 38.73 189.77 38.73 419.88 34.24 177.78 34.24 177.78 34.24 1 1 8 406.00 -154.97 53.51 25.03 416.82 -153.85 32.47 26.15 32.47 26.15 1 1 9 73.73 139.84 441.04 139.84 92.83 139.16 479.45 139.16 479.45 139.16

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maps and autobuild
by chandra bose 06 Apr '09

06 Apr '09

hello, I am a first time user to phenix , and I have just completed the autobuild function,. My question may have been asked many times before, but.. The output after the cycles of autobuild/refinement gave me a refined file for a 2.2 Angstrom data set with an R/Rfree of .28/.32. I want to take a look at the density modified maps and see what I can adjust further, but am having trouble loading it in coot. Am I correct in understanding that Coot can load and construct 2f0-fc maps? if so How? : exptl_fobs_phases_freeR_flags.mtz overall_best_denmod_map_coeffs.mtz; overall_best_refine_map_coeffs.mtz; Also from reading the manual, as I understand it, the phenix.refine command will automatically generate Coot compatible maps. But if I take my autobuild.pdb file and the original mtz data file, how can I quickly obtain the same R/Rfree, what commands would I have to imput other than phenix.refine mtz pbd? Also, is it possible to make 3Fo-2Fc maps? Thanks Charlie

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phenix.autobuild sa_omit map
by Jianghai Zhu 03 Apr '09

03 Apr '09

Hi, I am using phenix.autobuild to calculate a sa_omit map. The find_ncs is Auto by default. What does Auto mean here? Should I turn it off or does it matter? Thanks. -- Jianghai

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refinment of ligand
by peter hudson 02 Apr '09

02 Apr '09

Hello all I have refined and built model a dataset of 3.0A resolution dataset. This model is assocaied with a ligand. After final refinement and model building i found a big blob of Fo-Fc density of around 4sigma level at the N-terminal of the fianl model. My protein doesnot carry any tag at the N-terminal. But, the template i have used for the molecular replacement carrying a tag at the N-termianl, which can occupy only 1/4th of this positive density after superpostion. My crystallisation conditions component cannot occupy such higher level of positive density. Since my protein binds to a ligand, i looked carefully to the positive density and it seems very similar to the ligand density but its obscure. Refinement after fitting the ligand leads to very high B-factor of the ligan, which vary for various atoms from 50-90 and simultaneously positive density goes off. I also tried to change the occupancy of the ligand but as i reduce the occupancy the B factor comes down at the noraml expected average B factor value but again Fo-Fc density appears in the map over ligand. If i leave to refine the occupancy to the programme automatically, this lead to the zero occupancy of the few atoms in the ligand and avearge B factor remains normal. suggestions would be appreciated. Thanks in advance Peter

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phenix.autobuild disappeared
by Andreas Förster 01 Apr '09

01 Apr '09

Hey there, sorry for the brainfreeze but I can't find phenix.autobuild. It's not part of cci_apps Versions 2008_09_13_0905 or 2009_02_15_2320. What happened? How do I build? Andreas -- Andreas Förster, Research Associate Paul Freemont & Xiaodong Zhang Labs Department of Biochemistry, Imperial College London http://www.msf.bio.ic.ac.uk

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Re: [phenixbb] phenixbb Digest, Vol 40, Issue 31
by Marjolein Thunnissen 01 Apr '09

01 Apr '09

> > Hi Marjolein, > >> I have been trying to find in the documentation if there is a way to do this >> but I have the following problem: In a recent structure we are currently >> refining we identified a spermine molecule sitting right on a >> crystallographic two-fold axis. Spermine has internal two-fold symmetry and >> it is part of extensive crystal contacts. I just wonder how to refine this >> with Phenix. In Refmac it is easy, I put the occupancies to 0.5 and the >> program ignores the clashes of the symmetry related molecule, but that >> doesn't seem to be the way that Phenix works. Can anyone give me advise on >> this? > > Supporting the occupancy trick is on my to-do list (fairly high up). > > In the meantime, could you try giving only the asymmetric unit of the > spermine? I.e. delete all duplicate atoms from your pdb file. > The restraints across the symmetry bond will not work automatically. > You have to define a "custom bond" instead, and if you also want to > restrain the angles, custom pseudo-bonds. See the > "Definition of custom bonds and angles" section. > In your case you'll have to define symmetry_operations (not shown > in the docs), e.g.: > > bond { > action = *add > atom_selection_1 = resname SPM and name C7 > atom_selection_2 = resname SPM and name C7 > symmetry_operation = -x,-y,z > distance_ideal = 1.5 > sigma = 0.01 > } > > The main difficulty will be to find the correct symmetry_operation > for each custom bond. If you send my the CRYST1 card from your > PDB file and the part with the SPM residue I could help out. > > Ralf > > > ------------------------------ Hi, The commands worked indeed the trick. Luckily it is actually not that difficult to find the symmetry operators when using coot. One just has to switch drawing symmetry atoms on and clicking on a symmetry atom, coot will tell you in the bottom line which atom it is and which symmetry operator was used to draw it... Thanks again Marjolein __________________________________________________________________________ | Marjolein Thunnissen Phone +46-(0)46-22 24584| | Associate Professor Fax +46-(0)46-22 24692| | Dept of Molecular Biophysics, Lund University http://www.mbfys.lu.se | | PO-Box 124 S-221 00 Lund, Sweden | | | |Scientific coordinator I911 (Max-lab): MAD and fixed-wavelength stations | | for macromolecular crystallography | |__________________________________________________________________________|

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Re: [phenixbb] PHENIX user mailing list <[email protected]>
by Ralf W. Grosse-Kunstleve 31 Mar '09

31 Mar '09

Hi Maia, > I have a Ca2+ ion in a special position. the ocupancy should be 0.5, as > the other half belongs to a symmetry-related molecule. However, > refinement makes the occupansy 1. What should I do to prevent this? > Should not it find automatically that? phenix.refine uses the correct symmetry factor automatically (internally). Unless you have an actual partial occupancy, the occupancy factor in the pdb file should be 1, irrespective of the multiplicity of the special position. Let me know if this doesn't answer your question. Ralf

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can I turn off TLS for subsequent rounds of refinement?
by Scott Classen 30 Mar '09

30 Mar '09

Hi all, As the TLS refinement can take a significant amount of time, I'm wondering if I can turn it off after a few rounds with it on? or will phenix.refine "see" the ANISOU records and assume I am doing anisotropic ADP? Thanks, Scott

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