Hi, My first guess would be that this crystal possesses translational NCS, and that you're using the "old" (distributed with current old CCP4) version of Phaser that can't handle tNCS. You can tell if this is the case by looking at whether there's a large off-origin peak in the native Patterson map. If so, then you should try Molrep from the current CCP4 or a newer version of Phaser (recent Phenix release, or upcoming CCP4 release).
Regards, Randy Read On 19 Apr 2012, at 07:20, LISA wrote: > Hi all, > > I am trying to solve one structure by molecular replacement with phaser in > CCP4. This a complex of a multi-domain domains with small ligand. I have > structues of this protein in apo state and with other similar ligand. The > space group of this crystal is P21. This crystal should have 4 molecules in > ASU. I used the full protein as model but did get any sol and LLG is below > zero. Then each domain were used as the search models in phaser with rotation > and tranlsation. I can the get high z score (>20), and LLG is raising. It > looks like I get the right sol, but it have more 50 clashes. Why phaser > give wrong sol with so high z socre? Can anyone give me some suggestion to > solve my strucutes? Thank you. > Best > > Lisa ------ Randy J. Read Department of Haematology, University of Cambridge Cambridge Institute for Medical Research Tel: + 44 1223 336500 Wellcome Trust/MRC Building Fax: + 44 1223 336827 Hills Road E-mail: rj...@cam.ac.uk Cambridge CB2 0XY, U.K. www-structmed.cimr.cam.ac.uk
