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Re: [phenixbb] Pseudotranslation issue
by Gino Cingolani 07 Jun '13

07 Jun '13

Dear Fulvio, We just had a similar problem (further complicated by some twinning). Assuming that: 1. You collected enough data and 2. You don't have a crazy number of molecules in the tetragonal asymmetric unit, I would advice to scale your data in P1 and do MR in P1. Then use conventional refinement + model building to bootstrap a better model (most likely your initial model isn't as good). Rosetta may help, too. Then eventually go back to the tetragonal data with the improved search model and see if LLG and packing make sense. Gino **************************************************************** Gino Cingolani, Ph.D. Associate Professor Thomas Jefferson University Dept. of Biochemistry & Molecular Biology 233 South 10th Street - Room 826 Philadelphia PA 19107 Office (215) 503 4573 Lab (215) 503 4595 Fax (215) 923 2117 E-mail: gino.cingolani(a)jefferson.edu Website: http://www.cingolanilab.org **************************************************************** "Nati non foste per viver come bruti, ma per seguir virtute e canoscenza" ("You were not born to live like brutes, but to follow virtue and knowledge") Dante, The Divine Comedy (Inferno, XXVI, vv. 119-120) Fulvio Saccoccia <fulvio.saccoccia(a)uniroma1.it> wrote: >Dear phenixbb, > I have a data set collected at 2.2A resolution that I can integrate >in P4. Aimless, Phaser and Xtriage recognized a pseudotranslation >(34.6% of origin peak) at fractional coordinates 0.500 0.500 0.479 >(ORTH 46.7 46.7 37.4). However labelit.index run with >sublattice_allow=true search did not detect the pseudotranslation >vector. So far, any attempts to phase by molecular replacement was >unsuccesfull and I suspect that it could be due to incorrect assignement >of space group: > >Now, some questions arise: >1) does the pseudo translation exist or do not? >2) if translational NCS is present, could it mimic a P41/P42/P43 space >group? >3) in any case, any advices in order to properly deal with tNCS will be >of great help? > >I thank you in advance >Best wishes > >-- >Fulvio Saccoccia, PhD >Sapienza University of Rome >Dept. of Biochemical Sciences "A. Rossi Fanelli" >Piazzale Aldo Moro, 5 >00185 Rome (Italy) > >_______________________________________________ >phenixbb mailing list >phenixbb(a)phenix-online.org >http://phenix-online.org/mailman/listinfo/phenixbb > The information contained in this transmission contains privileged and confidential information. It is intended only for the use of the person named above. If you are not the intended recipient, you are hereby notified that any review, dissemination, distribution or duplication of this communication is strictly prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message. CAUTION: Intended recipients should NOT use email communication for emergent or urgent health care matters.

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Pseudotranslation issue
by Fulvio Saccoccia 07 Jun '13

07 Jun '13

Dear phenixbb, I have a data set collected at 2.2A resolution that I can integrate in P4. Aimless, Phaser and Xtriage recognized a pseudotranslation (34.6% of origin peak) at fractional coordinates 0.500 0.500 0.479 (ORTH 46.7 46.7 37.4). However labelit.index run with sublattice_allow=true search did not detect the pseudotranslation vector. So far, any attempts to phase by molecular replacement was unsuccesfull and I suspect that it could be due to incorrect assignement of space group: Now, some questions arise: 1) does the pseudo translation exist or do not? 2) if translational NCS is present, could it mimic a P41/P42/P43 space group? 3) in any case, any advices in order to properly deal with tNCS will be of great help? I thank you in advance Best wishes -- Fulvio Saccoccia, PhD Sapienza University of Rome Dept. of Biochemical Sciences "A. Rossi Fanelli" Piazzale Aldo Moro, 5 00185 Rome (Italy)

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rosetta installation problems
by Mengbin Chen 04 Jun '13

04 Jun '13

Dear Phenix Users, I am interested in using Rosetta to do MR, but unfortunately I have encountered some problems in installing it: I was able to get to the step where "scons: done building targets." showed up, and set up the environment by typing setenv /Users/yanghai/Desktop/rosetta-3.5 into the shell. I also filled out the "path to rosetta" in "Preferences" under "PHENIX GUI", which I believe it is correct. However, when I was ready to run MR-rosetta, it kept saying "cannot locate Rosetta programs. You may set the path in PHENIX GUI under preferences->Automation, or define the environment variable PHENIX_ROSETTA_PATH (recommended)". Any help would be apprecited! Thank you in advance, Mengbin Chen -- Mengbin Chen Department of Chemistry University of Pennsylvania

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EG4 not in phenix dictionary?
by Yarrow Madrona 03 Jun '13

03 Jun '13

Hello, I have previously refined EG4 and EG2 (tetra and diethylene glycol) as ligands and these were in the standard phenix library. I was under the impression that phenix shares the library from the CCP4 monomer library which I know should have EG4. Can anyone help me with this. I guess the alternative is to generate a restraints file. -Yarrow -- Yarrow Madrona Graduate Student Molecular Biology and Biochemistry Dept. University of California, Irvine Natural Sciences I, Rm 2403 Irvine, CA 92697

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MAX IV Life Science Director position
by Derek Logan 03 Jun '13

03 Jun '13

Hi, If anyone fancies becoming Life Science Director at the world's brightest light source, look no further than here: http://www.lunduniversity.lu.se/o.o.i.s?id=24914&Dnr=547454&Type=E /Derek ________________________________________________________________________ Derek Logan tel: +46 46 222 1443 Associate Professor mob: +46 76 8585 707 Dept. of Biochemistry and Structural Biology www.cmps.lu.se<http://www.cmps.lu.se> Centre for Molecular Protein Science www.maxlab.lu.se/node/307<http://www.maxlab.lu.se/node/307> Lund University, Box 124, 221 00 Lund, Sweden

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Re: [phenixbb] Discrepancy between R-factors from phenix.refine vs phenix Generate "Table 1"
by Michael Thompson 01 Jun '13

01 Jun '13

As another follow up to this point, I have had a recent example where Xtriage reported that my intensity statistics indicated twinning (<|L|>=0.399 and <L^2>=0.227, alpha=0.4). After having refined the structure with the suggested twin law, and making composite omit maps along the way (using autobuild with no twin law), I ran model vs. data at the end of refinement and noticed that it reported R/Rfree that were about 10% higher than the R/Rfree from refinement, similar to what the original post described. I checked the model vs. data logfile and found that the L-test routine used by model vs. data was failing, so the subsequent analysis was carried out as if there was no twinning. So in my case, the crystal was twinned, but model vs. data was not able to perform the L-test so it was outputting incorrect R-factors. The error message at the top of the model vs. data log file is: Twin analysis failed: Python argument types in l_test.__init__(l_test, miller_index, double, space_group, bool, float, float, float, int) did not match C++ signature: __init__(_object*, scitbx::af::const_ref<cctbx::miller::index<int>, scitbx::af::trivial_accessor> miller_indices, scitbx::af::const_ref<double, scitbx::af::trivial_accessor> intensity, cctbx::sgtbx::space_group space_group, bool anomalous_flag, long parity_h, long parity_k, long parity_l, unsigned long max_delta_h) Twin analysis failed: Python argument types in l_test.__init__(l_test, miller_index, double, space_group, bool, float, float, float, int) did not match C++ signature: __init__(_object*, scitbx::af::const_ref<cctbx::miller::index<int>, scitbx::af::trivial_accessor> miller_indices, scitbx::af::const_ref<double, scitbx::af::trivial_accessor> intensity, cctbx::sgtbx::space_group space_group, bool anomalous_flag, long parity_h, long parity_k, long parity_l, unsigned long max_delta_h) Perhaps there are some other users who are seeing this behavior because the L-test fails within model vs. data. Mike ----- Original Message ----- From: "Nathaniel Echols" <nechols(a)lbl.gov> To: "PHENIX user mailing list" <phenixbb(a)phenix-online.org> Sent: Wednesday, May 29, 2013 5:18:57 PM GMT -08:00 US/Canada Pacific Subject: Re: [phenixbb] Discrepancy between R-factors from phenix.refine vs phenix Generate "Table 1" On Wed, May 29, 2013 at 4:13 PM, Sam Stampfer <Samuel.Stampfer(a)tufts.edu> wrote: > When I refined my model in phenix, I used the twin law h,-h-k,-l. I read in > the documentation that twinning can account for some of this discrepancy, > but that the program is supposed to take twinning into account if it will > lower the calculated R-work by more than 2%, which it doesn't seem to have > done (or there is some other problem with my data). Okay, the problem is that your data don't actually appear to be twinned. The automatic method used by phenix.model_vs_data (which is used internally for Table 1 and the validation GUI) only tries possible twin laws if the results of the "L test" show a suspicious distribution of intensities. Your data look fine, so it doesn't bother trying the twin laws. That the R-factors are lower when you refine with a twin law isn't necessarily indicative of the data actually being twinned - Garib Murshudov has looked into this in detail but I confess to being ignorant of the math (but I can probably dig up his paper on the subject if anyone is interested). However, I'm pretty sure the data are actually in a higher-symmetry space group. Will send details and new files off-list (probably tomorrow at this rate). I should probably change some of the programs and/or documentation to make it more clear what is being done internally, since it took me a bit of digging to realize what was going on. In general, though, always be very careful before running twinned refinement! I have seen several users do this by mistake when they really had higher symmetry. The maps will also be more model-biased when using twinned refinement, so it's good to avoid doing this unless absolutely necessary. -Nat _______________________________________________ phenixbb mailing list phenixbb(a)phenix-online.org http://phenix-online.org/mailman/listinfo/phenixbb -- Michael C. Thompson Graduate Student Biochemistry & Molecular Biology Division Department of Chemistry & Biochemistry University of California, Los Angeles miket(a)chem.ucla.edu

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Re: [phenixbb] refinement of partly occupied water molecules?
by krimmer＠staff.uni-marburg.de 31 May '13

31 May '13

Dear Nathaniel, dear Pavel, thank you for your fast answers! > currently phenix.refine can add automatically only fully occupied > waters (I am not sure it will ever use atomic model for partially > occupied waters). If necessary, add partially occupied waters > yourself manually. Make sure they have properly set altlocs > (alternative location identifiers): non blank (say A and B). Is it current praxis to let phenix.refine freely refine the occupancy of water molecules (adding partially occupied water molecules in coot and don’t fix the occupancy in phenix)? If I do so, these water molecules are refined by phenix.refine with occupancies between 0.4-0.8. My resolution range was 1.1 – 1.4 Å. > The nightly builds have an option in phenix.refine to place ions > automatically based on a variety of criteria (still being tuned). > However, what you describe doesn't sound like any ion coordination > motif that I've read about. Could you please send us a picture that > shows the density in context? Some of the other readers with more > experience in "blobology" may recognize it. [if our list server > complains about the size of the message, just ignore it, I'll approve > it for posting] Attached you will find the image of the blob. I think it’s easily visible that the density blob is in the middle of the five-ring and that there is also a (smaller) blob in the middle of the six-ring. The water which occupies the blob was not yet refined with phenix, I just put it there to measure the distances to the carbon atoms. Best regards, Stefan

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gap between Wilson B and average B
by fn1＠rice.edu 30 May '13

30 May '13

Dear all, I have a structure at about 3.5 A, which has a wilson B of about 109 and has an average B factor from model is only 49 (I did not use TLS). I read from the previous posts that wilson B is sometimes smaller than average B, but in my case it is reversed. I look at the distribution of model B factors, they are in the range of 8 to 132. Is there any problem with the refinement of this structure? Thanks in advance for all advice! Regards, Fengyun

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refinement of partly occupied water molecules?
by krimmer＠staff.uni-marburg.de 30 May '13

30 May '13

Dear all, I have a question concerning the refinement of partly occupied water molecules: in some of my macromolecular crystal structures with resolutions between 1.1 - 1.4 Å, mainly in the second solvation shell round positive Fo-Fc electron density blobs are detectable which show after assignment of a water molecule to these blob and subsequent refinement with Phenix refine a good-looking calculated 2Fo-Fc electron density (round shape, the 2Fo-Fc map appears at a contour level of σ = 1.0 - 1.4), but there also occurs a small negative Fo-Fc electron density detectable inside the 2Fo-Fc density blob. The negative Fo-Fc electron density disappears if the occupancy of the water molecule is refined by Phenix or manually set lower than 100% occupancy. Therefore, I think these positions are partly occupied by water molecules, but I am not sure how I should handle it/how it is generally handled. I would be thankful for any advice and/or literature about this topic. My second question is concerning a density blob in perfect coordination distance to an indolyl group (perfectly located in the middle of the five-ring, with 3.4 Å distance to every of the five carbon atoms of the five-ring). What‘s the best way to find out which ion possibly occupies this position? I tried Na+ and Ca2+, but after refinement big negative Fo-Fc blobs appear in both cases (maybe the ion at this position is only partly occupied?). There is no anomalous signal detectable at this position (data collection wavelength was 0.91841 nm). After the refinement of a water molecule at this position, a positive Fo-Fc election density is still there. Thank you for your help! Stefan

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R-merge
by Mengbin Chen 29 May '13

29 May '13

Dear Phenix Users, I have R-merge values equal 0.000 from highest resolution shell (which corresponds to values larger than 1.000) in a data set processed by HKL2000, with redundancies higher than 10 (I know this may help in increasing R-merge). I am not sure if this is going to be a problem of Table 1 for the reviewers. Could you kindly drop me your suggestions? Thank you in advance, Mengbin Chen -- Mengbin Chen Department of Chemistry University of Pennsylvania

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