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Refining coordinates
by Subhani Bandara 10 Jan '14

10 Jan '14

Dear all, I have a protein crystallized with metal chelate complexes and some of the atoms of chelators and the metals sit on the two fold axis. Is there a way that I can refine the coordinates of those atoms only along the two fold axis (let's say X) while restraining the coordinate refinement along other two axes (Y and Z)? Thanks Subhani

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fwd: Announcement: International Summer School of Crystallography - May 2014, Hamburg, Germany
by Nathaniel Echols 10 Jan '14

10 Jan '14

---------- Forwarded message ---------- From: "Oberthuer, Dominik" <dominik.oberthuer(a)cfel.de> To: phenixbb(a)phenix-online.org Date: Fri, 10 Jan 2014 16:14:08 +0100 Subject: Announcement: International Summer School of Crystallography - May 2014, Hamburg, Germany Dear colleagues, we are pleased to announce the first International Summer School of Crystallography at the Center for Free-Electron Laser Science at DESY, Hamburg (D). As part of the International Year of Crystallography 2014, Prof. Carmelo Giacovazzo will give a full week of lectures on the basics of crystallography, as well as the basics of modern phasing methods in protein crystallography. The course will cover basic mathematical understanding of crystallographic point and space groups, diffraction experiments, structure factor calculations, systematic absences, determination of space groups and many additional topics. After the discussions of theory, one afternoon will be spent to learn about modern applications of protein crystallography using advanced light sources, such as 3rd generation synchrotron and XFELs. The course will be given mainly for PhD students working in the field of crystallography, but exceptions for motivated PostDocs and MSc students can be made. The course will mostly cover mathematical background of crystallography, hence we are looking for students, having a (bio)physics background. This will NOT be a workshop covering protein crystallographic programs but rather the theory behind those programs. The course will start Sunday (11.05.2014) around lunch and will end Saturday (17.05.2014) around lunch. The registration fee is 100 EUR per person including coffee breaks and lunch. Accommodations can be made at the DESY Guest House: 70 EUR per person for 7 nights (10.-17.05.2014). Application deadline will be 28th of February 2014 and notification of accepted applications will be sent during March 2014. The applications will be managed via the DESY Indico system: https://indico.desy.de//event/ISSC14 Applicants must provide a motivation letter, as well as a CV, directly to the organizer Cornelius Gati (cornelius.gati(a)cfel.de). Places and accommodation are limited to 30 students in total. Please contact Cornelius Gati regarding further questions ( cornelius.gati(a)cfel.de). We are looking forward to welcome you in Hamburg! -- Dr. Dominik Oberthür CFEL - Center for Free-Electron Laser Science Coherent Imaging Division and University of Hamburg Laboratory for Structural Biology of Infection and Inflammation Notkestrasse 85 22607 Hamburg Germany phone: +49 (0)40 8998 6394 dominik.oberthuer(a)cfel.de obertuer(a)chemie.uni-hamburg.de

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Low F-obs Values
by 张怀东 06 Jan '14

06 Jan '14

Hi, everyone I used phenix-1.8.2-1309 to do MR and Autobuild, then Refinement, the max F-obs value of the mtz file from refinement was about 300. However, I used phenix-1.8.4-1496 to do the same work, the max F-obs value was about 3000. The resulting structure models donot seem to be any different. We tried several datasets of different proteins, and the max F-obs value are low with phenix-1.8.2-1309. So is this a real problem or not? Best regards Huaidong Zhang

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I remind you: Please apply for RapiData 2014, a course on Data Collection and Structure Solving at the NSLS.
by Robert Sweet 06 Jan '14

06 Jan '14

We are offering RapiData 2014, the sixteenth offering of our popular course: Rapid Data Collection and Structure Solving at the NSLS: A Practical Course in Macromolecular X-Ray Diffraction Measurement The course will be held 27 April - 2 May 2014: http://www.bnl.gov/RapiData/. Students could be at any level from advanced undergraduate to full professor. The course should accommodate 48 students total. We encourage all students to bring their own specimens for data collection, and to bring old data for the data-reduction and structure-solving tutorials. Please read the Course Announcement at http://www.bnl.gov/RapiData/. You'll see that many experts in the field will be available for lectures and tutorials. In addition to MX there will be opportunity for learning about correlated MX and spectroscopy, and SAXS. You'll find the application materials on the Course Application tab at this site. For the twelfth time we will hold a short lecture course on the fundamentals of crystallography for roughly five hours on Sunday 27 April. The body of the RapiData course really requires that students have a healthy knowledge of crystallography. For potential students who have some experience but are shaky about fundamentals, this course will help. There will be an additional fee for the fundamentals course, to pay for Saturday night accomodations and food on Sunday morning and noon. Latin American Scientists: Several scholarships are available, from the International Union of Crystallography, to pay partial travel and subsistence costs for Latin-American students and junior faculty (no more than 30 yrs). Please apply for the course, and then contact R. Sweet (sweet(a)bnl.gov) if you are interested in applying for a scholarship. In accordance with the standards of the International Union of Crystallography, we observe the basic policy of non-discrimination, affirming the right and freedom of scientists to associate in international scientific activity without regard to such factors as citizenship, religion, creed, political stance, ethnic origin, race, colour, language, age, or gender, in accordance with the Statutes of the International Council for Science. At this course no barriers will exist beyond the application procedure that would prevent the participation of bona fide scientists. Please apply yourself, or send your students to our course, Bob Sweet, Sonya Kiss, and Alex Soares Course Announcement at http://www.bnl.gov/RapiData/ ========================================================================= Robert M. Sweet E-Dress: sweet(a)bnl.gov Group Leader, PXRR: Macromolecular ^ (that's L Crystallography Research Resource at NSLS not 1) http://px.nsls.bnl.gov/ Photon Sciences and Biosciences Dept Office and mail, Bldg 745, a.k.a. LOB-5 Brookhaven Nat'l Lab. Phones: Upton, NY 11973 631 344 3401 (Office) U.S.A. 631 344 2741 (Facsimile) =========================================================================

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Postdoc positions (SGC, Diamond): fragments into crystals
by Frank von Delft 02 Jan '14

02 Jan '14

Hello, I have 3 open postdoc positions, to work on technologies around fragment screening in crystals, which is what my (joint) research team at Diamond (beamline I04-1) and SGC (PX group) is trying to make simple and accessible. Details of the project are on my website <http://www.thesgc.org/scientists/groups/oxford/crystallography>; we need smart people to: * (at SGC) test-drive with start-to-end soaking campaigns <http://www.thesgc.org/careers/oxford/crystallography-postdoc-fragment-scree…> * (at SGC) develop crystal engineering to get soakable systems (molecular biology, biochemistry) <http://www.thesgc.org/careers/oxford/crystallography-postdoc-crystal-engine…> * (at Diamond) explore soaking techniques <http://www.diamond.ac.uk/Home/Jobs/Current/DIA0886_CH.html> The application deadlines for the SGC posts are a function of the UK's charming political climate; if you're interested but from outside the EU, alert me with a direct email plus CV. phx. P.S. if you know smart undergrads who'd be interested in a DPhil in that sort of thing -- applied engineering, technology -- send them to that website too. (DPhils are what you get in Oxford - that makes it special. Or "special".)

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Multiple conformation, two ligands
by YANG HAI 31 Dec '13

31 Dec '13

Dear Phenix Community, I tried to model two ligands one of which has two conformations. In other words, the two scenarios are: 1) ligand X with conformation A (XA, 75% occupancy); 2) ligand X with conformation B (XB, 25% occupancy) plus another ligand Y. However, the problem is ligand Y will have steric clash with ligand XA. If I rename ligand X and Y to the same residue name then I do not know how to define the CIF file. I apologize if this question was asked before and I do not know how Phenix or other refinement can deal with multiple conformation a group of ligands. Thanks. Happy new year! Yang Hai Christianson Lab University of Pennsylvania

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phenix morph- no shift problems
by Ming Sun 29 Dec '13

29 Dec '13

Hi Everyone I'm currently trying running phenix.morph model on a large complex. However, after 5 cycles of running, there were no shift at all. And we set data, model, map_coeffs, reference_restraints, morph_main.. Does anyone happen to have similar issues? Any specific parameter I should change? Thanks again -Ming

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Reduce NQH
by jp d 19 Dec '13

19 Dec '13

hi, we were going through the logs recently and see something odd during Reduce N/Q/H analysis the log file looks like this: ================================== NQH flips ================================== r_work=0.3047 r_free=0.3518 Analyzing N/Q/H residues for possible flip corrections... segID AL01 renamed chain A for Reduce N/Q/H analysis segID AL02 renamed chain B for Reduce N/Q/H analysis ... segID AL29 renamed chain Y for Reduce N/Q/H analysis segID AL30 renamed chain Z for Reduce N/Q/H analysis segID AL32 renamed chain a for Reduce N/Q/H analysis segID AL33 renamed chain a for Reduce N/Q/H analysis segID AL34 renamed chain b for Reduce N/Q/H analysis segID AL35 renamed chain b for Reduce N/Q/H analysis ... segID BL28 renamed chain z for Reduce N/Q/H analysis segID BL31 renamed chain z for Reduce N/Q/H analysis segID BL13 renamed chain AA for Reduce N/Q/H analysis segID BL29 renamed chain AB for Reduce N/Q/H analysis ... we noticed that the lower case chain letters start to duplicate themselves and are not unique to each segid. when it starts the two letter chain, everything seems unique again. forgive me if that is expected, it just seems kind of strange this was seen in mutlple log files and we are using version Version: 1.8.4 Release tag: 1496 if you need our files or more details, let me know thanks jpd

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ensemble refinement rfree values
by Arjun Raman 19 Dec '13

19 Dec '13

Dear Phenix Guys, I have recently been trying my hand at the ensemble refinement option in phenix.refine. I generally observe an increase in rfree after performing the ensemble refinement with a well refined (using anisotropic B) structure, but the r-free increases are fairly small. For instance, 18.53% to 18.9% (1.8 Angstrom structure) or 20.45% to 21.1% (1.9 A)...I understand what this technically means (the ensemble refined model isn't as good) but given the noise in the calculation due to the limited number of reflections for the test set (~1000), would someone consider these rfree increases significant? My apologies if this question is a well-answered one...I can't seem to find much discussion about the range of rfrees to be expected or whether a 0.3-0.5% increase is large enough to toss out the refinement. Normally, I would take the lower rfree but because the ensemble refinement procedure gives potentially much more information, this seemed like a relevant question to ask. Thanks so much for your time, Arjun Raman Ranganathan Lab UT Southwestern ________________________________ UT Southwestern Medical Center The future of medicine, today.

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MR-SAD, Yb, combined phases
by Joseph Noel 19 Dec '13

19 Dec '13

Hi All, I am carrying out a structure refinement using experimental phases combined with an MR solution. The experimental phases are being determined from bound Yb3+ cations and the data is collected at one of the Yb absorption peaks of 1.385 A. I do have a few questions about the heavy atom arrangement and then refinement. At this wavelength, I am also seeing peaks after running MR-SAD that are actually not the Yb cations but the sulfurs on several of the proteins Cys and Met residues. Should I try and change this "heavy atom arrangement" to include Yb and S before determining the final refined phases that I would like to then use as restraints during the structure refinement? If so, its not clear how to do this in Phenix without it finding additional sites that it attributes to Yb but which are actually sulfurs. For MR, this is an exact structure. All I am doing is using Yb which substitute for Mg coordination sites as a source of experimental phases to see how it improves refinement and maps. Second, when I do refine using the MLHL target function, I am finding quite a bit of excess positive density around the Yb sites. How do I try and account for this? I have attempted to take care of it with ADP and occupancy refinement but that doesn't seem to be enough. The resolution is 2.2 A and the anomalous signal is quite good (alas that is why I am also seeing the sulfurs clearly in the anomalous difference map). Do I need to change the scattering table since the structure now includes at least 4 Yb cations per asymmetric unit (one 550 amino acid residue protein per asymmetric unit - 68% solvent)? Is it important to refine the anomalous groups? For the latter, one can't refine with phase restraints (MLHL) and anomalous groups together. I have to choose one or the other - no phase restraints and anomalous groups refined, or experimental phase restraints and no anomalous group refinement. My goal is to use additional experimental measurements - amplitudes and phases to improve refinement, map interpretation and ultimately ensemble refinement. Any help, comments, criticisms, etc will be very appreciated! Happy Holidays! Joe ______________________________________________________________________________________ Joseph P. Noel, Ph.D. Arthur and Julie Woodrow Chair Investigator, Howard Hughes Medical Institute Professor, The Jack H. Skirball Center for Chemical Biology and Proteomics The Salk Institute for Biological Studies 10010 North Torrey Pines Road La Jolla, CA 92037 USA Phone: (858) 453-4100 extension 1442 Cell: (858) 349-4700 Fax: (858) 597-0855 E-mail: noel(a)salk.edu Publications & Citations: http://scholar.google.com/citations?user=xiL1lscAAAAJ Homepage Salk: http://www.salk.edu/faculty/noel.html Homepage HHMI: http://hhmi.org/research/investigators/noel.html ______________________________________________________________________________________

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