- phenixbb - phenix-online.org

Berkeley servers are back in service
by Billy Poon 03 Aug '17

03 Aug '17

Hi everybody, The servers at Berkeley are now available. Please let us know of any issues. Thanks! -- Billy K. Poon Research Scientist, Molecular Biophysics and Integrated Bioimaging Lawrence Berkeley National Laboratory 1 Cyclotron Road, M/S 33R0345 Berkeley, CA 94720 Tel: (510) 486-5709 Fax: (510) 486-5909 Web: https://phenix-online.org

1 0

Lab Evac
by Nigel Moriarty 03 Aug '17

03 Aug '17

Folks The Grizzly Fire (the media loves a interesting name) is more than 50% contained and the lab is now open. The servers are, once again, available for downloading the latest version of Phenix, 1.12. Cheers Nigel --- Nigel W. Moriarty Building 33R0349, Molecular Biophysics and Integrated Bioimaging Lawrence Berkeley National Laboratory Berkeley, CA 94720-8235 Phone : 510-486-5709 Email : NWMoriarty(a)LBL.gov Fax : 510-486-5909 Web : CCI.LBL.gov

1 0

Emergency shutdown
by Nigel Moriarty 02 Aug '17

02 Aug '17

Folks Phenix servers are shutting down due to a grass fire in the area. Cheers Nigel --- Nigel W. Moriarty Building 33R0349, Molecular Biophysics and Integrated Bioimaging Lawrence Berkeley National Laboratory Berkeley, CA 94720-8235 Phone : 510-486-5709 Email : NWMoriarty(a)LBL.gov Fax : 510-486-5909 Web : CCI.LBL.gov

1 0

Postdoctoral position in Structure and Function of Fungal Membrane Proteins
by Maike Bublitz 02 Aug '17

02 Aug '17

Postdoctoral position in Structure and Function of Fungal Membrane Proteins A post-doctoral position is available in the research group of Associate Prof. Maike Bublitz at the Department of Biochemistry, University of Oxford. The project aims to understand the structure and function of fungal membrane transport proteins identified as potential new drug targets, using a combination of state-of-the-art structural (X-ray crystallography, cryo-EM) and biochemical/biophysical techniques. Applicants should hold a PhD in a relevant subject area, such as membrane protein biochemistry or structural biology. Experience in native or recombinant membrane protein expression, purification and either structural determination or functional analysis using biochemical and biophysical techniques is essential. Ability to work in a team as well as contribute to supervision activities and excellent verbal and written communication skills are expected. Experience in protein X-ray crystallography and/or cryo-EM is an advantage. To apply for this role and for further details, including the job description and selection criteria, please click on the link below: https://www.recruit.ox.ac.uk/pls/hrisliverecruit/erq_jobspec_details_form.j… Applications for this vacancy are to be made online by 31th August 2017.

1 0

(no subject)
by Priyanka Abeyrathne 21 Jul '17

21 Jul '17

1 0

Phenix version 1.12 released
by Paul Adams 14 Jul '17

14 Jul '17

The Phenix developers are pleased to announce that version 1.12 of Phenix is now available (build 1.12-2829). Binary installers for Linux, Mac OSX, and Windows platforms are available at the download site: http://phenix-online.org/download/ Highlights for this version: New tools for secondary structure validation, comparing multiple related structures, cryo-EM model and map validation, and calculation of real space difference maps. Video tutorials are now available on the new Phenix Tutorial YouTube channel (www.youtube.com/c/phenixtutorials). A suite of tools for cryo-EM model building and structure refinement including automated map sharpening, segmentation, and model building. Real space refinement now has an option to use histogram equalized map as a refinement target. Phaser version 2.8 has several new features, including unit cell refinement for EM data, more extensive use of eLLG in decision making and analysis, anomalous substructure determination (Phassade), improved tNCS detection and analysis, and improvements to SCEDS. - NEW TOOLS - phenix.secondary_structure_validation - tool to validate secondary structure section in .pdb and .mmcif files with option to filter bad annotations. - Structure Comparison: tool for parallel validation and analysis of near-identical protein structures. Results include the analysis of ligands, rotamers, Ramachandran angles, missing atoms, water locations and B-factors. - phenix.mtriage: command-line tool to validate cryo-EM models. GUI is available. Computes various map statistics including resolution estimates, FSC between half-maps, full and model maps. Outputs mask file used to compute FSC. Still under development. - phenix.real_space_diff_map: command-line tool to compute difference map. This is a real-space analogue of Fo-Fc map mainly designed for cryo-EM maps. See http://phenix-online.org/newsletter/CCN_2017_01.pdf for details. - PHENIX VIDEO TUTORIALS Video tutorials about Phenix tools are now available on the Phenix Tutorial YouTube channel (www.youtube.com/c/phenixtutorials). The following topics are covered: - How to run phenix.refine - How to calculate polder maps - How to run phenix.real_space_refine - How to run PDB tools - How to change phenix.refine parameters via the GUI - Basic Phenix eLBOW tutorial - How to run Phaser-MR from the Phenix GUI - Explaining the atom selection syntax - How to run Structure Comparison - NEW FEATURES - Phenix.auto_sharpen: New map sharpening algorithms available based on (1) optimization of map clarity (adjusted surface area or kurtosis), (2) resolution-dependent map-model correlation, (3) resolution-dependent half-map correlation, and (4) local map sharpening - Phenix.map_to_model: Iterative map improvement using model from one cycle to optimize sharpening of the map for the next cycle - Phenix.map_to_object: Now you can individually map each member of a group of chains onto your target - Phenix.chain_comparison: Now can compare a target to each of a group of models - Phenix.find_alt_orig_sym_mate: Now uses ssmalignment.stats to see what residue pairs were included by ssm in a hypothetical calculation of the ssm-rmsd. This is to avoid including atoms that even for an optimal structural alignmentwould have been too far apart that ssm would use them. Excluding these is necessary to avoid having the calculated rmsd blow up. - Now using angles for restraining hydrogen bonds in alpha helices and beta sheets in secondary structure restraints. - Phenix.polder: New option (compute_box=True) to compute a difference map excluding the bulk solvent mask within a user-defined box. The map can be used to inspect interesting difference density peaks. - phenix.map_model_cc (phenix.model_map_cc): various enhancements and bug fixes. - phenix.real_space_refine: - improved ADP refinement (still group) - improved NCS constraints definition - multi-model PDB file is not output by default anymore - (experimental) option to use masked histogram equalized map as refinement target. Using such map dramatically improves refined model geometry. This map is not suitable for ADP refinement. - show CCmask, CCvolume and CCpeaks that report on local and gloabal model to map fit. - RESTRAINTS - Specialised restraints for ligands with differing chemistry in the same model allows using the same 3-letter code but different restraints for a specific instance - apply_cif_restraints - Detailed control of peptide planes and omega angles - apply_all_trans - apply_peptide_plane - apply_cis_trans_specification: use an atom selection (CA) to force a cis or trans omega angle - REEL - Improvements to robustness and features - GUI - New interfaces - phenix.mtriage - phenix.map_box - phenix.auto_sharpen - phenix.map_to_model - phenix.ncs_average (under "Other Tools") - phenix.sculpt_ensemble (alpha) - Updated interfaces - Comprehensive Validation shows real-space correlations from phenix.map_model_cc when map files are used - Structure Comparison - Validation - improved speed of clashscore validation - bug fix to handling of cis-peptides in ramalyze - contours for ramalyze, rotalyze, and cablam now accessible at https://github.com/rlabduke/reference_data - validation GUI now shows altloc identifirs for most outliers - improved internal code accessibility of validation statistics - Phaser-2.8.0 - refinement of cell for data (electron micrcoscopy) - more analysis using eLLG for component addition - more analysis using eLLG for polyalanine residues for target eLLG given rms - more analysis using eLLG for single atoms more ordered than average - more analysis using eLLG for chains/gyre-and-gimble * Phassade: Fast Fourier Transform Anomalous Substructure Determination - SOLU TRIAL records RF-LLG for trial orientation - gyre and translation function report RF recorded for trial orientations - 'scons --ccp4' command line flag for ccp4 build (generates ccp4-style headers) * improved tNCS detection and analysis * gyre and gimble improved for output and python scripting * NMA outputs all perturbed files in MODEL delimited pdb file '<fileroot>.nma.pdb' * sceds outputs domains to chain delimited file '<fileroot>.nma.pdb' - sceds domain pdb file have TER separated domains - NMA option to output separate pdb files for each perturbation (XYZOUT NMA ALL OFF) - sceds option to output separate pdb files for each domain (XYZOUT NMA ALL OFF) - NMA has option to turn off output of input coordinates (NMA ORIG ON) - pdb chain identifies can be left unchanged from input (XYZOUT CHAIN COPY) (for Eleanor) - bugfixes -- allow peaks and purge percent to override one another if not default -- rms estimation developer options not being set correctly -- throw out of memory error if Patterson map allocation fails For a full list of changes see: http://www.phenix-online.org/documentation/CHANGES Please note that this publication should be used to cite use of Phenix: PHENIX: a comprehensive Python-based system for macromolecular structure solution. P. D. Adams, P. V. Afonine, G. Bunkóczi, V. B. Chen, I. W. Davis, N. Echols, J. J. Headd, L.-W. Hung, G. J. Kapral, R. W. Grosse-Kunstleve, A. J. McCoy, N. W. Moriarty, R. Oeffner, R. J. Read, D. C. Richardson, J. S. Richardson, T. C. Terwilliger and P. H. Zwart. Acta Cryst. D66, 213-221 (2010). Full documentation is available here: http://www.phenix-online.org/documentation/ There is a Phenix bulletin board: http://www.phenix-online.org/mailman/listinfo/phenixbb/ Please consult the installer README file or online documentation for installation instructions. Direct questions and problem reports to the bulletin board or: help(a)phenix-online.org and bugs(a)phenix-online.org Commercial users interested in obtaining access to Phenix should visit the Phenix website for information about the Phenix Industrial Consortium. The development of Phenix is principally funded by the National Institute of General Medical Sciences (NIH) under grant P01-GM063210. We also acknowledge the generous support of the members of the Phenix Industrial Consortium. -- Paul Adams Division Director, Molecular Biophysics & Integrated Bioimaging, Lawrence Berkeley Lab Division Deputy for Biosciences, Advanced Light Source, Lawrence Berkeley Lab Adjunct Professor, Department of Bioengineering, U.C. Berkeley Vice President for Technology, the Joint BioEnergy Institute Laboratory Research Manager, ENIGMA Science Focus Area Building 33, Room 347 Building 80, Room 247 Building 978, Room 4126 Tel: 1-510-486-4225, Fax: 1-510-486-5909 http://cci.lbl.gov/paul Lawrence Berkeley Laboratory 1 Cyclotron Road BLDG 33R0345 Berkeley, CA 94720, USA. Executive Assistant: Louise Benvenue [ LBenvenue(a)lbl.gov ][ 1-510-495-2506 ] --

1 0

Problem with smiles string in elbow
by Edward A. Berry 13 Jul '17

13 Jul '17

I'm not getting the expected result with this string: COC(=O)C(=COC)c1ccccc1COC(N1C)=CC(=N1)C(=C2O)C=C(Cl)C=C2 When used with coot Lidia it gives the expected result (upper picture). But when I run elbow like this: phenix.elbow --smiles="COC(=O)C(=COC)c1ccccc1COC(N1C)=CC(=N1)C(=C2O)C=C(Cl)C=C2" --output="Y7303" --id="Y03" the result is the lower picture. In particular the pyrazole ring (arrow) gets distorted, but other bond lengths are way off. I want to use elbow because it names the atoms as numbered in the order they appear in the smiles string, irrespective of the element. This is good because this is one of a series of compounds in some of which C's are replaced by N's and vice versa so it helps to have the same number for atoms in the same position. What does work is to save the structure as .mol from Lidia and feed that to elbow, which gives the right structure and the elbow atom names. But it would be good to find out why it isn't working directly. my elbow is: electronic Ligand Builder & Optimisation Workbench (eLBOW) 1.12rc1-2801 None

1 0

Problem with rotamer refinement
by Renato Ferras 11 Jul '17

11 Jul '17

Dear all, I am refining a protein structure at 1.74 A resolution with phenix.refine (version 1.10.1_2155) and I have noticed that some side chains don't remain in the electronic density even after careful hand adjustment in which they are almost perfect. It seems pretty clear where the side chain should (must) be located, moreover it is consistent with two rotamers (either rotamer tp60 - #4 in coot - or rotamer tp-100 - #9 in coot -, which are approx. at 180 deg for chi3). In spite of that, after reciprocal space refinement, I observe that the end of side chain rotates chi3 angle and both N and O gets far from where they started (there is this difference in the chi3 angle). My concerns are about the proper interpretation of geometrical restraints listed in .geo file, specially what the ideal value is, how weights are applied to ideal value and why phenix doesn't reach convergence in reciprocal space refinement. Below are the values from .geo for the referred Gln: dihedral pdb=" CB GLN B 21 " pdb=" CG GLN B 21 " pdb=" CD GLN B 21 " pdb=" OE1 GLN B 21 " ideal model delta sinusoidal sigma weight residual 0.00 23.41 -23.41 2 3.00e+01 1.11e-03 8.42e-01 is there a description for us to interpret what these numbers are? To my understanding, the ideal values are established as being either 0 or 180 degrees (yet sinusoidal 2). I cannot say about how heavy the weights are on these (in fact, I left my refinement to optimize weights), but anyway, if I understand correctly, the ideal value (for chi3) should be rotamer dependent. Taking Gln as an example, I see several rotamers do have values close to either 0 or 180 degree, but what about rotamers 4 and 9? I might imagine a similar situation for residues like Asn and His, though I have not searched deep for these yet. Thanks, Renato

2 1

crystal imaging system
by Sebastiano Pasqualato 30 Jun '17

30 Jun '17

Dear all, we are in the process of considering the purchase of a new Crystal Imager. So far, we have been considering the Formulatrix Rock Imager 182 and the TriTek Crystal Pro HT. I would be extremely grateful to anyone who could provide me: - feedback and user experience (positive/negative) on those instruments; - information on other instruments you would suggest. Thank you very much in advance, wishing you a pleasant weekend, best regards, ciao, S -- Sebastiano Pasqualato, PhD Crystallography Unit Department of Experimental Oncology European Institute of Oncology IFOM-IEO Campus via Adamello, 16 20139 - Milano Italy tel +39 02 9437 5167 fax +39 02 9437 5990 web http://is.gd/IEOXtalUnit

2 1

Phenix polder error
by Avinash Punekar 26 Jun '17

26 Jun '17

Dear all, When I run phenix.polder through command line, I get a message "Sorry: Multiple equally suitable arrays of observed xray data found." and phenix.polder stops without producing the maps. How to solve this problem? Any help is highly appreciated. Thanks, Avinash

2 1

does phenix refine fill in missing data?
by Ursula Schulze-Gahmen 22 Jun '17

22 Jun '17

I have very anisotropic data. I used the staraniso webserver to analyse and process my data which creates a final merged file with very incomplete data in the outer shells. If I use this data file in Phenix, what will happen? Will Phenix automatically fill in the unobserved data? If so, can I prevent it from doing so? I am importing the data with the reflection file editor and it seems the reflections are being filled in already at this stage. Ursula -- Ursula Schulze-Gahmen, Ph.D. Project Scientist UC Berkeley, QB3 360 Stanley Hall #3220 Berkeley, CA 94720-3220 (510) 643 9491

2 1

Cif file recognition
by Joel Tyndall 21 Jun '17

21 Jun '17

Hi there, Having a few minor issues with my phenix setup on windows 10. I have the latest stable build Phenix1.11.1-2575. When introducing a new ligand that exists in the monomer library, Pheix complains it does not have the geometry restraints (cif file) - somehow it is not seeing its own library. How can I set up the cif library as default? Cheers Joel Joel Tyndall | BSc(Hons) PhD Associate Professor in Medicinal Chemistry School of Pharmacy | Te Kura Mātauraka Wai-whakaora University of Otago | Te Whare Wānanga o Otāgo PO Box 56 9054 Dunedin | Ōtepoti New Zealand | Aotearoa Ph: 64 3 479 7293 Skype: jtyndall Website | pharmacy.otago.ac.nz

2 1

sculptor modifications
by Emilia C. Arturo (Emily) 21 Jun '17

21 Jun '17

Hello All, Is there a way to identify quickly the changes to a model that Sculptor has made? I am running the Phenix GUI to use Sculptor. I have read through the out-put log file, and understand (mostly) the sculpt protocol as it relates to the circumstances under which modifications to main chain or side chains are made, but it would be nice to see (in a list format, perhaps) what changes (if any...) were made. Regards, Emily. -- "Study as if you were going to live forever; live as if you were going to die tomorrow." - Maria Mitchell "I'm not afraid of storms for I'm learning to sail my ship." - Louisa May Alcott

4 3

phenix.map_to_model input mtz file failure
by dancingdream＠163.com 18 Jun '17

18 Jun '17

Dear Phenix bb, I intend to build a initial model by phenix.map_to_model. And the command line is as follows: phenix.map_to_model_1.12rc0-2787 map_coeffs_file=../rep_dm.mtz map_coeffs_labels="'FP,SIGFP' 'PHIDM' 'FOMDM'" seq_file=../resolve.seq is_crystal=True use_sg_symmetry=True density_select=False truncate_at_d_min=True and the feedback like this: Sorry: No initial assignment made for map_coeffs. Labels used: FP,SIGFP PHIDM FOMDM. Available labels: ['PHIB', 'FOM', 'HLA,HLB,HLC,HLD', 'FP,SIGFP', 'PHIDM', 'FOMDM', 'FDM', 'HLADM,HLBDM,HLCDM,HLDDM'] NOTE: grouped labels like 'FP,SIGFP' must stay together, have commas, and have no spaces. If they come from an MTZ file, they must be in adjacent columns as well. Suggested labels to use: PHIDM FOMDM I try many other input format of map_coeffs_labels, such as map_coeffs_labels="FP,SIGFP PHIDM FOMDM" map_coeffs_labels=["FP,SIGFP PHIDM FOMDM"] ... ... but the result is the same. Dose anyone can tell me how to fix this problem? Thank a lot. -- Wei Ding P.O.Box 603 The Institute of Physics,Chinese Academy of Sciences Beijing,China 100190 Tel: +86-10-82649083 E-mail: dingwei(a)iphy.ac.cn

7 20

Overall anisotropic ADP in phenix.real_space_refine?
by Oliver Clarke 17 Jun '17

17 Jun '17

Hi, I wonder in phenix.real_space_refine whether it may be worth adding refinement of a single overall anisotropic ADP to the model - or a single TLS group with modeled anisotropic ADPs - in order to model the effects of overall orientation errors (which affect resolution more substantially towards the periphery) and preferred orientation (which tends to give rise to anisotropic resolution across the volume). Maybe this would be helpful at least in generating a calculated map that is better for difference map calculation, for example? Cheers Oli

1 0

real_space_refine questions
by Daniel Larsson 14 Jun '17

14 Jun '17

I'm have some questions about doing real space refinements using phenix.real_space_refine. I am refining a model for an intermediate-resolution (3.79 Å) cryo-EM map. As the starting point I use a model from a higher-resolution map (3.25 Å) of the same system in another conformation. My idea is to first do rigid body fitting of domains and then gradually relax constrains and restraints. - Is it possible to restrain the position of certain parts of the model (i.e. "freeze" them so that they move at all) to do focused refinement of subdomains or loops? - In the instructions it says that you can do both NCS constraints and restraints. How you do the latter? I can only do the former by default or by defining ncs_constraints=True and give a NCS definition file. - When I do a run with run=rigid_body, some rigid body groups move in to each other and overlap. Is there no collision detection using this algorithm? If I do a run=minimization_global, things work a bit better in this regard, but is not really what I want (at this stage). Am I doing something wrong? Here is the run command and the rigid body definition file: phenix.real_space_refine \ model.pdb \ map.ccp4 \ rigid.eff \ resolution=8.0 \ ncs_constraints=False \ rotamer_restraints=True \ ramachandran_restraints=True \ c_beta_restraints=True \ run=rigid_body \ macro_cycles=10 # rigid.eff: refinement { rigid_body { group = chain A and resseq 101:266 group = chain A and resseq 273:388 group = chain B and resseq 101:266 group = chain B and resseq 273:388 group = chain C and resseq 104:266 group = chain C and resseq 273:388 } } Regards, Daniel Larsson

3 3

Computational Crystallography Newsletter (CCN) submissions
by Nigel Moriarty 13 Jun '17

13 Jun '17

Folks Calling for articles and short communications of interest to structural biologists. The initial deadline for submission for the July 2017 issue is 30 June 2017. The Computational Crystallography Newsletter (CCN) is an electronic newsletter for structural biologists, and is published online every 6 months. Feature articles, meeting announcements and reports can be submitted to me at any time for consideration. Submission of text by email or word-processing files using the CCN templates is requested. Past newsletters and a Microsoft Word template are available at www.phenix-online.org/newsletter. Cheers Nigel --- Nigel W. Moriarty Building 33R0349, Molecular Biophysics and Integrated Bioimaging Lawrence Berkeley National Laboratory Berkeley, CA 94720-8235 Phone : 510-486-5709 Email : NWMoriarty(a)LBL.gov Fax : 510-486-5909 Web : CCI.LBL.gov

1 0

preparing DL-Malic acid stock solution
by Sebastiano Pasqualato 08 Jun '17

08 Jun '17

Dear all, we’ve recently having trouble preparing a 3 M stock solution of DL-Malic Acid, pH 7 (which we had, so it’s doable!). When we reach pH 3 - 4 the solution turns milky white and does not goes back to a clear solution even when the pH is raised. Does anybody have any advice on how to get a clear solution? Has anyone gone through the same? Thanks in advance, ciao, Sebastiano -- Sebastiano Pasqualato, PhD Crystallography Unit Department of Experimental Oncology European Institute of Oncology IFOM-IEO Campus via Adamello, 16 20139 - Milano Italy tel +39 02 9437 5167 fax +39 02 9437 5990 web http://is.gd/IEOXtalUnit

1 0

Re: [phenixbb] AutoSol invalid MTZ column_types error
by Terwilliger, Thomas Charles 08 Jun '17

08 Jun '17

Hi Mintu, I'm sorry about this problem! I should have fixed it already but missed this message from Phil Evans that he posted in January: "Columns N(+) and N(-), both of type I, are recent additions to the output file from Aimless. They are the number of observations merged into I(+) and I(-) respectively" AutoSol doesn't know about these columns and can accidentally guess that they are data. To get around this column, use a command like this to create a data file that does not contain the N(+) and N(-) columns: phenix.reflection_file_converter aimless.mtz --mtz=aimless_noN.mtz --label="I(+" ?where the --label=xxxx command specifies the first few characters of the columns you want to use as I+/I- data. Then use aimless_nonN.mtz instead of aimless.mtz as input to autosol. I will fix this in autosol. Let me know if that does not do it! All the best, Tom T Dear all, I am getting an error message "Invalid MTZ column_types for the given miller_array." while I try to run AutoSol. The last line in the log is "Adding array ['N(+)', 'N(-)'] to output file with type II". Do you have any suggestion how to fix this error? Thanks a lot in advance. Best, Mintu

1 0

comfortable OS X level
by Patrick Loll 07 Jun '17

07 Jun '17

I’m still running Yosemite on my Macs, both because I’m change-averse and because folks reported problems with some crystallographic software upon upgrading the OS. These reports have now faded into the haze of the past, and so I ask, have the issues been resolved? Is it safe to move to Sierra? Thanks as always, Pat --------------------------------------------------------------------------------------- Patrick J. Loll, Ph. D. Professor of Biochemistry & Molecular Biology 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

3 2

ligand - protein close contact
by Nikos Pinotsis 06 Jun '17

06 Jun '17

Dear all, I have a protein-ligand structure with several chains in the AU. After refinement one of the ligands forms a close contact 1.8A with the protein. For the rest of the protein-ligand chains the same interaction is as expected to 2.7-2.8 A forming an H-bond. I tried to adjust this ligand with coot but everytime I am getting back the same 1.8 A close contact. There is enough density for the ligand and I can even see that it can fit better to distance 2.4-2.5A H-bond with the protein Is there a way to constrain this distance to more than 2A? Should I fix the ligand atom that interacts? Unless I am missing something more fundamental. The ligand cif file is the default in phenix, the data set is a quite decent 2.3A. thanks in advance for any suggestions Nikos -- Dr. Nikos Pinotsis Institute of Structural and Molecular Biology Department of Biological Sciences, 3rd Floor, R313 Birkbeck College Malet Street London WC1E 7HX T: +44 (0)207 631 6827 F: +44 (0)207 631 6803 M: +44 (0)792 384 3593

3 3

Composite omit map
by Sam Tang 05 Jun '17

05 Jun '17

Dear all Sorry for a very basic question about generating an omit map. I am trying to generate a SA-omit map for only my ligand but not the protein core of my complex. I presume I can use phenix.composite_omit_map GUI and specify my ligand chain in Atom Selection? All other parameters being the same, I notice that when I did not select any atom the whole structure was divided to 30-40 regions but when I selected my ligand chain it now divides into 89 regions. Is there a reason why and is there any advantage to manually adjust the number of omit regions? Many thanks and regards Sam Biochemistry Programme, School of Life Sciences, CUHK

3 5

Fitting ligand with DM map?
by Sam Tang 03 Jun '17

03 Jun '17

Dear community I guess it may not be a standard practice but I wonder if anyone has tried to use a density modified map for ligand building. My situation is that I am trying to fit a single strand DNA ligand into an enzyme model. The dataset is at 3 Ang, P1 space, with overall completeness of only about 88%. MR was done by the apo-enzyme and the density for the first two-third of the ligand is very good and could easily be modelled. Towards the last one-third the density becomes much weaker so nucleotides cannot be easily put. This is the only dataset so far, so multi-crystal averaging / map averaging is not possible at this stage. NCS averaging is also not possible. We did try to sharpen map during refinement. I understand that DM is usually used to improve phase at the initial stage esp. with experimental phasing. With MR would you think density modification could produce a better map to aid the modelling of the last one-third ligand? Can I use the denmod.mtz directly for manual model building? Any input would be very much appreciated. Best Sam Biochemistry Programme, CUHK

2 1

Questions on TLS output and more info on phenix.tls
by Michael Garavito 29 May '17

29 May '17

I am finishing the final stages of refinement with TLS at 1.7 Å and want to begin some B-factor analysis. Also, I am setting up for a series of ensemble refinements. However, I am second guessing myself and have been finding that several basic questions that are not explicitly answered by the Phenix documentation. (1) Just to be sure, I looked for the definition of what is written in the ATOM records of the output PDB file after refinement with TLS: residual B or total B (residual B + TLS contribution). I always thought the latter after refinement with TLS, but nothing was explicitly stated. (2) Also, I have looked for it extensively in the Phenix documentation, I have not found any information on phenix.tls, even though in several places (e.g., phenix.ensemble_refinement), there are explicit references to phenix.tls: “If TLS is used the TLS components must be present in the atom records (see phenix.tls)” The information from just doing % phenix.tls -h does not give enough insight into options and there use. Can someone point me to the right place to get these answers? Thanks, Michael **************************************************************** R. Michael Garavito, Ph.D. Professor of Biochemistry & Molecular Biology 513 Biochemistry Bldg. Michigan State University East Lansing, MI 48824-1319 Office: (517) 355-9724 Lab: (517) 353-9125 FAX: (517) 353-9334 Email: garavito(a)msu.edu ****************************************************************

2 1

Linking C-Type Heme
by Julian Esselborn 23 May '17

23 May '17

Hi list, that might sound like a stupid question, but we are having some trouble getting phenix.refine acknowledging a c-type linkage of a heme. That is a covalent Cys SG bond to C18 or C25 in the heme. The pdb file does contain a LINK record for this, but Ready Set seems to ignore that even if told to look for LINK records. The distance in the model is actually around 1.9 Ä and automatic ligand linking is on and set well below that distance. Any ideas why this might be failing and what is the smartest way to proceed? Any ideas highly appreciated. Thanks a lot Julian Esselborn Tezcan Lab UC San Diego

2 1