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secondary structure restraints
by Nikos Pinotsis 11 Aug '08

11 Aug '08

Dear all, I am refinining a 3.5 A structure where several of fragments are already determined in higher resolution (similar to the case I found below). In addition a large part of the structure is quite disordered (two out of four chains). I found a reply about a year ago that secondary structure restraints are not implemented in phenix, is there any new developements that can help the refinement in low resolution? (I have already employed NCS other common posibilities). thank you in advance for any help and best regards Nikos >/ On May 4, 2007, at 5:10 PM, Pavel Afonine wrote: />/ />>/ Hi Jianghai, />>/ />>/ I see several possibilities to think about or/and try out: />>/ />>/ 1) Fix the coordinates of atoms in the domains for which the high />>/ resolution structure is available and refine the rest; />>/ 2) Refine the domains for which the high resolution structure is />>/ available as rigid bodies and for the rest refine individual parameters; />>/ 3) There is no specific option in phenix.refine to restrain the />>/ secondary structure elements, however there is a tedious way of doing />>/ this (according to Ralf) by defining custom bonds and angles between />>/ specific atoms forming the secondary structure motifs. Look />>/ "Definition of custom bonds and angles" in the latest CCI Apps />>/ phenix.refine documentation for technical details. />>/ />>/ You can perform "1)" and "2)" in ONE refinement run by combining />>/ several refinement strategies and using specific selections for />>/ refinable parameters. />>/ />>/ Overall, at 3.8A resolution the refinement of individual atomic />>/ parameters (coordinates, B-factors) is questionable. I would consider />>/ to try to refine group parameters for B-factors (trough TLS or/and />>/ group B (like one B per residue)) and try to switch between rigid />>/ body refinement of smaller fragments of your model and refinement />>/ individual positional parameters or mix of individual and rigid body />>/ refinement. />>/ />>/ Also, I will think about making a specific option for automatic />>/ generation of secondary structure restrains. However, given the />>/ amount of work it may require this option will not appear in near future. />>/ />>/ Pavel. />>/ />>/ />>/ Jianghai Zhu wrote: />>>/ Hi all, />>>/ />>>/ I am refining a low resolution structure (~3.8 A). For some of the />>>/ domains in the structure, we already have high resolution />>>/ structures. Despite of some conformational changes in some loops, />>>/ the core structures should be the same. I am wondering if it is />>>/ possible to restrain the secondary structures in phenix.refine. />>>/ />>>/ Thanks. />>>/ />>>/ Jianghai/ -- --------------------------------- Dr. Nikos Pinotsis Section of Structural Biology Institute of Cancer Research Chester Beatty Laboratories 237 Fulham Road London SW3 6JB, UK Tel: +44 20 7153 5453 / 5447 --------------------------------- The Institute of Cancer Research: Royal Cancer Hospital, a charitable Company Limited by Guarantee, Registered in England under Company No. 534147 with its Registered Office at 123 Old Brompton Road, London SW7 3RP. This e-mail message is confidential and for use by the addressee only. If the message is received by anyone other than the addressee, please return the message to the sender by replying to it and then delete the message from your computer and network.

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dihedral error
by Simon Kolstoe 08 Aug '08

08 Aug '08

phenix.refine keeps on stopping with the error: AssertionError: Conflicting dihedral restraints: tor id: var_002 1. definition from: residue: DRG, conformer A 2. definition from: residue: DRG, conformer A atoms: " CB DRG A 500 " " OG1 DRG A 500 " " PAL DRG A 500 " " OAF DRG A 500 " It is for a phospho-threonine residue whose dictionary I made in PRODRG. I've tried all the different charge states of the phosphate however phenix gives the same error every time. Any ideas? Thanks, Simon

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ncs in phenix.autobuild
by wang kaituo 07 Aug '08

07 Aug '08

Hi all, I failed in running phenix.autobuild. The end of the logfile said : ______________________________________________________ Build cycle 2 of 11 method:rebuild ...Using simple_ncs_from_pdb to find NCS Residues expected: [62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74] Residues found : [] ******************************************************************************** Failed to carry out AutoBuild_build_cycle: Did not find expected residues in get_xyz_list _____________________________________________________________ The two ncs chain sequence is not exactly same , some sidechain missing and some connectivity not well. But the residue 62-74 is there in both chains. Have the ncs group to be exactly same to find NCS? how can i fix this? ps: phenix.simple_ncs_from_map works well with my pdb. using the ncs_spec file also not works many thanks kaituo

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riding hydrogens
by Jianghai Zhu 06 Aug '08

06 Aug '08

Hi, I used phenix.reduce to add riding hydrogens. After phenix.refine, the structure got a good score from MolProbity. However, if I stripped the riding hydrogens from the structure and let MolProbity to add hydrogens before the analysis, I got a much worse score, especially the clash score. Does phenix.refine refine the hydrogen positions? -- Jianghai

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DNA restraints
by jens j birktoft 06 Aug '08

06 Aug '08

Hi, Is there a way to restrain selected hydrogen bonds between base pairs during the refinement of DNA structures ? CNS has something like DNA_RNA.def if I remember correctly and I am looking for something of that nature. Cheers Jens -- Jens J. Birktoft - e-mail: jens.knold(a)gmail.com slow-mail: 350 Central Park West, Suite 9F, New York, NY 10025 use 212-749-5057 for ALL phone calls

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Deborah Palestrant is out of the office.
by deborah.palestrant＠novartis.com 05 Aug '08

05 Aug '08

I will be out of the office starting 08/05/2008 and will not return until 08/11/2008.

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torsion angle dynamics simulated annealing?
by Bryan W. Lepore 04 Aug '08

04 Aug '08

i was wondering if someone could comment on any possibility of implementing torsion angle dynamics in phenix's simulated annealing procedure, in a future release of phenix? i.e. is that "in the works"? thanks! -bryan 1

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phenix.refine: Override 'Number of bonds with excessive lengths'
by Martin.Laurberg 04 Aug '08

04 Aug '08

Dear All, Is there a way to override the phenix.refine Setup Restraints Manager, preventing phenix.refine from terminating if the model features a lot of excessive bond lenghts? Thanks, /Martin ========================== Set up restraints manager ========================== .... Bonds with excessive lengths: Distance model: 50.2364 (ideal: 1.525) ATOM 1336 C3' DC B 20 12.611 28.560 12.463 1.00 42.81 C ATOM 1338 C2' DC B 20 -11.801 15.989 54.531 1.00 42.03 C .... Sorry: Number of bonds with excessive lengths: 71 -- Martin Laurberg, PhD Noller Laboratory 225 Sinsheimer Laboratories University of California at Santa Cruz CA-95064 Santa Cruz USA Tel +1 (831) 459 35 84 Fax +1 (831) 459 37 37

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Wishful thinking with AutoBuild?
by Francis E Reyes 04 Aug '08

04 Aug '08

Hello all Given a mediocre to bad experimental density map, what hopes does AutoBuild have of building a model? i.e. Should I be able to tell clear helicies and side chain density in the experimental density map before even attempting an autobuild? Thanks FR --------------------------------------------- Francis Reyes M.Sc. 215 UCB University of Colorado at Boulder gpg --keyserver pgp.mit.edu --recv-keys 67BA8D5D 8AE2 F2F4 90F7 9640 28BC 686F 78FD 6669 67BA 8D5D

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GUI inactivity
by David Hoover 04 Aug '08

04 Aug '08

We have RedHat Enterprise Linux 5, and the Phenix installation went just fine. When I fired up the GUI, it looked ok, but the inset was blank. Many of the buttons seemed inactive as well. Is there any support for installation beyond that on the web page? David Hoover, Helix Systems Staff, CIT/NIH

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