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OASIS-2006. Institute of Physics Chinese Academy of Sciences Beijing 100080, P.R. China. http://cryst.iphy.ac.cn. OASIS ( 2000 ). in CCP4. OASIS - 2004. on the Web. OASIS - 2006. on the Web soon. OASIS-2006 GUI for CCP4i. Functions of OASIS. 1. Direct-method 2. Reciprocal-space.
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OASIS-2006 Institute of Physics Chinese Academy of Sciences Beijing 100080, P.R. China http://cryst.iphy.ac.cn
OASIS (2000) in CCP4 OASIS-2004 on the Web OASIS-2006 on the Web soon
OASIS-2006 GUI for CCP4i
Functions ofOASIS 1. Direct-method 2. Reciprocal-space Dual-space Fragment Extension by combining with DM, RESOLVE and ARP/wARP SAD/SIR Phasing Fragment Extension
Why direct methods? For better initialSAD phases!
Bimodal distribution from SAD Cochran distribution Sim distribution Peaked at Peaked at any where from 0 to2p The phase of F” Phase information available in SAD
Sim-modified phases PSim PBimodal PSim PCochran P+ P + P+ P+-modified phases Two different kinds of initial SAD phases
Comparisonof 4 typical reflections from the protein histone methyltransferase SET 7/9
Histone methyltransferase SET 7/9 Comparison of cumulative phase errors in descendingorder ofFobs Number of reflections Errors of Sim-modified phases (o) Errors of P+-modified phases (o) 1500 57.1 45.8 3000 57.1 49.1 4500 56.5 50.0 6000 57.0 51.2 7500 57. 8 52.9 9000 58.7 54.1 10500 59.4 55.6 12000 60.8 56.9 13500 61.9 58.4 15000 63.4 60.2 16352 65.2 62.3
Why dual-space? For less systematic errors!
Dual-space fragment extension Real-space fragment extension RESOLVE BUILD and/or ARP/wARP Reciprocal-space fragment extension OASIS + DM Partial model OK? No Yes End Partial structure
Ab initio SAD phasing with weak anomalous signal
OASIS-DM-RESOLVE BUILD cycle 0 25% OASIS-DM-ARP/wARP cycle 6 99% SHARP-DM-RESOLVE BUILD SHARP-SOLOMON-ARP/wARP BP3-DM-RESOLVE BUILD Xylanase Space group: P21 Unit cell: a = 41.07, b = 67.14, c = 50.81Å b = 113.5o Number of residues in the ASU: 303 Resolution limit: 1.75Å; Multiplicity: 15.9 Anomalous scatterer: S(5 ) X-rays:synchrotron radiation l = 1.488Å; D f ” = 0.52 Bijvoet ratio:<|DF |>/<F > = 0.56% Data courtesy of Dr. Z. Dauter, National Cancer Institute, USA
SAD phasing at different resolutions TT0570 Cu-Ka data, <|DF|>/<F> ~ 0.55% 3.5Å 2.1Å 4.0Å
SOLVE/RESOLVE results improved by OASIS + DM
Dual-space fragment extensionbased on SOLVE/RESOLVE results 1LIA (d14)2.8Å SIR data SOLVE/RESOLVE + OASIS-DM-(RESOLVE BUILD) SOLVE/RESOLVE
Dual-space fragment extensionbased on SOLVE/RESOLVE results 2GW1 3.3Å SAD data Sigma_A map based on a model manually built from the SOLVE/RESOLVE map SOLVE/RESOLVE map OASIS-DM map based on the same model
Dual-space fragment extensionbased on SOLVE/RESOLVE results 2GW1 3.3Å SAD data SOLVE/RESOLVE map Sigma_A map OASIS-DM map
Fragment extension based on Molecular replacement
DM-ARP/wARP-OASISiteration Final model DM-ARP/wARP iteration MR model Cycle 2 Cycle 3 Cycle 1 acidic phospholipase A2 124 residues 48 residues 60 residues Cycle 11 Cycle 9 Cycle 13 DM-ARP/wARP iteration Fragment extension based on molecular replacement
Dual-space Fragment Extension without SAD/SIR information
Model building by RESOLVE BUILD or ARP/wARP Density modification by DM Phase improvement by OASIS MR model No Yes OK? End Partial structure
P+ > 0.5 j” + Dj = jmodel <|Dj|> ~ 90o <2|Dj|> ~ 180o |Dj| j” |Dj| • P+ < 0.5 • j” - Dj • jmodel - 2|Dj|
Sample:1UJZ Space group: I 222 Unit cell: a=62.88, b=74.55, c=120.44Å Number of residues in ASU: 215 molecule A: 87 residues molecule B: 128 residues Resolution range: 37.57 – 2.10Å Number of reflections: 16460
DM-ARP/wARP-OASIS iteration Cycle 2 Cycle 1 Cycle 7 Cycle 5 Cycle 3 Cycle 4 MR model 54 residues DM-ARP/wARP iteration Final model 215 residues 1UJZ
Participants of this project Staffs Hai-fu Fan1, Yuan-xin Gu1, Tao Jiang2, Zheng-jiong Lin2 & Chao-de Zheng1 Ph.D. students Jian-rong Chen1, Qiang Chen3, Yao He1, Sheng Huang1,4, He Li2, Jia-wei Wang1, Li-jie Wu1, De-qiang Yao1,5 & Tao Zhang1,6 1 Institute of Physics, CAS, Beijing, China 2 Institute of Biophysics, CAS, Beijing, China 3 Peking University, Beijing, China 4 Institute of High Energy Physics, CAS, Beijing, China 5 Univ. of Science & Technology of China, Hefei, China 6 Lanzhou University, Lanzhou, China
Acknowledgements SAD data used in this presentation were kindly provided by Dr. Z. Dauter1, Dr. S. J. Gamblin2, Dr. B. D. Sha3, Prof. I. Tanaka4, Dr. N. Watanabe4 & Dr. B. Xiao2 1 Argonne National Laboratory, USA 2 The National Institute for Medical Research, UK 3 Department of Cell Biology, University of Alabama at Birmingham, USA 4 Graduate School of Science, Hokkaido University, Japan