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Detecting and dealing with Pseudotranslation and/or twinning
by Hamaoka, Brent 12 May '11

12 May '11

I’ve been working on a troublesome protein structure. The native protein forms crystals that diffract to 2.75A and belong to P212121 (55.179 64.316 233.748 90.000 90.000 90.000) with 4 molecules in the ASU. I have 3 versions of the same protein where selenomethionine mutations are incorporated at different positions. Interestingly, these mutations cause the protein to form crystals belonging to C2221 (56.130 64.665 240.854 90.000 90.000 90.000). Looking back at the native datasets, Xtraige indicates the largest Patterson peak is (0.5, 0.486, 0), height is 11.8% of the origin peak, and p_value(height) is 0.08549, which is just outside of the threshold for being identified as containing pseudotranslation. Datasets from a couple of the selenomet incorporated crystals yield diffraction to ~3.5A and anomalous signal to ~6.7A. Some of the datasets give a solution with reasonable maps, but the best maps are achieved from combining MAD/SAD selenomet datasets and one from a mercury derivatized crystal using the ‘group’ command in Phenix. --------------------------------------------------------------------------- 5: STEP: finished Top solution: # 39 Dataset #0 BAYES-CC: 69.2 +/- 13.4 FOM: 0.6 Built: 219 Side-chains: 44 Chains: 9 CC: 0.74 Score type: SKEW CORR_RMS NCS_OVERLAP Raw scores: 0.41 0.82 0.00 100x EST OF CC: 69.17 43.34 31.25 --------------------------------------------------------------------------- Maps from this solution show connected electron density that looks like helices, consistent with the predicted secondary structure. Strangely, there is absolutely no side-chain density, only c-beta at most. I can build a poly-ala model into the map and the distances between the heavy atom sites appear correct based upon the known positions of the selenomethionines and the single cysteine in the protein sequence. However the model does not refine. R-free starts and remains near 0.45. I’ve tried indexing in lower symmetry space groups (P2, C2, P1) and re-solving by molecular replacement, but the refinement still fails. Xtriage does not indicate twinning. Twinning and intensity statistics summary (acentric data): Statistics independent of twin laws <I^2>/<I>^2 : 2.305 <F>^2/<F^2> : 0.758 <|E^2-1|> : 0.788 <|L|>, <L^2>: 0.501, 0.333 Multivariate Z score L-test: 1.643 The multivariate Z score is a quality measure of the given spread in intensities. Good to reasonable data are expected to have a Z score lower than 3.5. Large values can indicate twinning, but small values do not necessarily exclude it. One possible clue as to what is going on comes from analysis of SOLVE results. I was analyzing whether SOLVE/PHENIX solutions were related with one another by various origin shifts and came across one particular SOLVE run from a SeMet SAD dataset in C2221 that gave good statistics for a solution FOM=0.57, Z-score=20.26, peak height between 7.1 and 10.8 for 4 SeMet sites to 3.8A). The maps, however, looked poor. What was interesting, though, was that 2 of the Se sites matched well with where I was expecting the Se sites in one molecule in the asymmetric unit. The other two matched with where I would expect the sites in the other molecule when the model is shifted by one half the unit cell distance along the ‘a’ or ‘b’ axis. I’d appreciate any advice as to what might be happening, and how might I go about detecting the problem, and how to dealing with the data? Brent Hamaoka UC San Diego 9500 Gilman Drive 0375 La Jolla, CA 92093

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problem with version 1.7.1-743 linux
by Daniel PANNE 12 May '11

12 May '11

I get the following error only in 1.7.1-743 but not in 1.7_650. Any idea? Thanks, Daniel ******************************************************************************* ERROR: Unused parameter definitions: refinement.main.compute_optimal_errors (file "P1_refine_rigid.eff", line 257) refinement.pdb_interpretation.peptide_link.use_finite_differences (file "P1_refine_rigid.eff", line 514) refinement.secondary_structure.h_bond_restraints.substitute_n_for_h (file "P1_refine_rigid.eff", line 977) refinement.secondary_structure.h_bond_restraints.restrain_initial_values (file "P1_refine_rigid.eff", line 983) refinement.secondary_structure.h_bond_restraints.sigma (file "P1_refine_rigid.eff", line 984) refinement.secondary_structure.h_bond_restraints.slack (file "P1_refine_rigid.eff", line 985) refinement.secondary_structure.h_bond_restraints.h_o_distance_ideal (file "P1_refine_rigid.eff", line 986) refinement.secondary_structure.h_bond_restraints.h_o_distance_max (file "P1_refine_rigid.eff", line 987) refinement.secondary_structure.h_bond_restraints.n_o_distance_ideal (file "P1_refine_rigid.eff", line 988) refinement.secondary_structure.h_bond_restraints.n_o_distance_max (file "P1_refine_rigid.eff", line 989) ******************************************************************************* Sorry: Unused parameter definitions: Please check the input file(s) for spelling errors and obsolete parameter definitions. To disable this error message, add --unused_ok to the command line arguments.

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Technician Position available in Milan
by Sebastiano Pasqualato 12 May '11

12 May '11

Dear all, a technical position is available to work in the Crystallography Unit of the IFOM-IEO-Campus in Milan. (http://www.ifom-ieo-campus.it/joinus/detail_jobs.php?docuID=1566) The position is available immediately, and will be granted until March 2012. We are looking for a person who will be involved in the general management of the Unit's instrumentation, and who will take care of gathering samples from the Unit users, set up crystallization trials and perform biophysical experiments. Hence, we look for a person capable of independently organizing her/his work and with a great attitude to relate with people and work in a team. To apply, please send your CV, together with the name of at least one referee. Informal inquiries are welcome. cheers, Sebastiano PS: sorry for the double posting to those subscribed to both mailing lists. -- Sebastiano Pasqualato, PhD Crystallography Unit IFOM-IEO Campus Cogentech - Consortium for Genomic Technologies via Adamello, 16 20139 - Milano Italy tel +39 02 9437 5172 fax +39 02 9437 5990

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Multiple pdb entries in phenix.fmodel
by zhangh1＠umbc.edu 11 May '11

11 May '11

Hi, I just wonder for the huge systems which have been split multiple pdb entries, if I provide all the pdb files in a single script of phenix.refine: phenix.fmodel A.pdb B.pdb C.pdb data.mtz whether everything will go correctly? Or I have to merge them into a single pdb and renumber all atoms sequentially? Thanks!

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Re: [phenixbb] mr_rosetta
by Thomas C. Terwilliger 11 May '11

11 May '11

Hi Jermaine, I am sorry for the trouble! I am wondering if rosetta is working quite right? Can you possibly run the regression tests on mr_rosetta: phenix_regression.wizards.test_command_line_rosetta_quick_tests and see if that helps diagnose the problem? All the best, Tom T >> I have been trying a standard run of mr_rosetta and I have stopped at the >> same point (output below). 32 folders were created in the >> GROUP_OF_RESCORE_MR_ROSETTA_1 folder and the mr_rosetta.log files all say >> that saved overall results to a .../results.pkl and the Run log file >> states >> that each job finished. But no further files were written in the Work >> folder >> under each RUN folder and I am assuming there should be a folder with my >> final 20 Rosetta models somewhere. Does this mean there was a failure in a >> subscript? >> ============================================================================== >> >> Starting sub-processes Group of rescore MR rosetta:Rescoring set of >> rosetta >> models... >> ============================================================================== >> >> Splitting work into 32 jobs and running with 4 processors using sh >> background=True in ....MR_ROSETTA_1/GROUP_OF_RESCORE_MR_ROSETTA_1 >> >> Starting job 1...Log will be: >> ..../MR_ROSETTA_1/GROUP_OF_RESCORE_MR_ROSETTA_1/RUN_FILE_1.log >> Starting job 2...Log will be: >> ..../MR_ROSETTA_1/GROUP_OF_RESCORE_MR_ROSETTA_1/RUN_FILE_2.log >> >> thanks, >> JJ >> _______________________________________________ >> phenixbb mailing list >> phenixbb(a)phenix-online.org >> http://phenix-online.org/mailman/listinfo/phenixbb >>

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mr_rosetta
by Jermaine Jenkins 11 May '11

11 May '11

I have been trying a standard run of mr_rosetta and I have stopped at the same point (output below). 32 folders were created in the GROUP_OF_RESCORE_MR_ROSETTA_1 folder and the mr_rosetta.log files all say that saved overall results to a .../results.pkl and the Run log file states that each job finished. But no further files were written in the Work folder under each RUN folder and I am assuming there should be a folder with my final 20 Rosetta models somewhere. Does this mean there was a failure in a subscript? ============================================================================== Starting sub-processes Group of rescore MR rosetta:Rescoring set of rosetta models... ============================================================================== Splitting work into 32 jobs and running with 4 processors using sh background=True in ....MR_ROSETTA_1/GROUP_OF_RESCORE_MR_ROSETTA_1 Starting job 1...Log will be: ..../MR_ROSETTA_1/GROUP_OF_RESCORE_MR_ROSETTA_1/RUN_FILE_1.log Starting job 2...Log will be: ..../MR_ROSETTA_1/GROUP_OF_RESCORE_MR_ROSETTA_1/RUN_FILE_2.log thanks, JJ

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Low Resolution Density Modification Problems
by Ian Slaymaker 10 May '11

10 May '11

I am having a problem getting a decent DM map at lower resolutions (8, 10, 12, 20). We have a model for the data (R-factor ~34) at 6.6 A (the model is based on different higher resolution data), and when I try and do DM at anything worse than 6.6, the density no longer covers the model. Any suggestions would be appreciated. Ian Slaymaker USC <http://www-scf.usc.edu/%7Eslaymake/>

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Different R-free values
by Jerome Nwachukwu 10 May '11

10 May '11

Dear all: I find that phenix.refine reports a higher starting R-free than those stated for structures downloaded from the PDB. For instance, the R-free stated in the PDB = 0.287, using Polygon = 0.2880, but the Start R-free from phenix.refine = 0.3114 Is this usual, or is something seriously wrong? Thank you, -Jerome Jerome C. Nwachukwu, PhD Dept. of Cancer Biology The Scripps Research Institute-Florida 130 Scripps Way, 2C1 Jupiter, FL 33458

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error from loop fitting
by Kendall Nettles 09 May '11

09 May '11

I'm trying the loop fitting for the first time and keep getting this error: Reading in sequence probability info and matching to input PDB List of segments read from input PDB file: Segment 0 Start: 225 End: 380 ChainID: 'A' NO MATCH What should be in the sequence file? it is fasta format?it is the entire sequence, or just the loop? I've played with different combinations and keep getting the same error. Best regards, Kendall Nettles

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Diffraction anisotropy
by Ina Lindemann 06 May '11

06 May '11

Hi, I am refining a structure of 2.3A resolution. The R values with and without bulk solvent and anisotropic scale are quite different as you can see here: Start R-work = 0.3751, R-free = 0.5562 (no bulk solvent and anisotropic scale) Final R-work = 0.3741, R-free = 0.5557 (no bulk solvent and anisotropic scale) Start R-work = 0.2298, R-free = 0.2974 Final R-work = 0.2261, R-free = 0.2970 I checked the anisotropy of the data with different tools: Results from Xtriage: Maximum likelihood isotropic Wilson scaling ML estimate of overall B value of None: 39.25 A**2 Estimated -log of scale factor of None: -2.59 Maximum likelihood anisotropic Wilson scaling ML estimate of overall B_cart value of None: 50.10, 0.00, 0.00 50.10, -0.00 25.47 Equivalent representation as U_cif: 0.63, -0.00, -0.00 0.63, 0.00 0.32 Eigen analyses of B-cart: Value Vector Eigenvector 1 : 50.103 ( 0.71, 0.71, -0.00) Eigenvector 2 : 50.103 (-0.71, 0.71, -0.00) Eigenvector 3 : 25.473 (-0.00, 0.00, 1.00) ML estimate of -log of scale factor of None: -2.57 Correcting for anisotropy in the data Results from PHASER: Principal components of anisotropic part of B affecting observed amplitudes: eigenB (A^2) direction cosines (orthogonal coordinates) 8.178 0.9961 0.0879 0.0000 8.178 -0.0879 0.9961 0.0000 -16.357 -0.0000 -0.0000 1.0000 Anisotropic deltaB (i.e. range of principal components): 24.535 Results from Ctruncate: ANISOTROPY CORRECTION (using intensities): Anisotropic scaling (orthogonal coords): | -0.2272 -0.0000 -0.0000 | | -0.0000 -0.2272 0.0000 | | -0.0000 0.0000 0.4543 | Anisotropic U scaling (fractional coords): | -4.451e-05 -5.622e-23 -1.266e-21 | | -5.622e-23 -4.451e-05 -8.929e-22 | | -1.266e-21 -8.929e-22 4.717e-06 | Anisotropic B scaling (fractional coords): | -3.514e-03 -4.439e-21 -9.995e-20 | | -4.439e-21 -3.514e-03 -7.050e-20 | | -9.995e-20 -7.050e-20 3.725e-04 | Eigenvalues: 0.7728 0.7728 1.4543 Eigenvalue ratios: 0.5314 0.5314 1.0000 Resolution limit in weakest direction = 3.156 A Now I am not sure about the severeness of anisotropy and the necessary procedure and would be very pleased if anyone could help. The electron density maps look okay related to the resolution. Has anyone experience with the diffraction anisotropy server or ellipsoidal truncation with data with comparable anisotropy? Thank you for your help in advance Ina Ina Lindemann Philipps-Universität Marburg Pharmazeutische Chemie AG Klebe Marbacher Weg 6 35032 Marburg Tel.: 06421/2825908

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