We solved recently a structure with 18 dimers in the a.u. related by translational symmetry. Molrep did a great job at quickly placing all molecules but few. The missing ones were found later by map inspection. We found rather important to play with the resolution cutoff.
I understand new versions of Phaser can also handle pseudotranslation very effectively. Good luck. R ________________________________ From: CCP4 bulletin board [CCP4BB@JISCMAIL.AC.UK] On Behalf Of Ke, Jiyuan [jiyuan...@vai.org] Sent: Monday, April 30, 2012 4:41 PM To: CCP4BB@JISCMAIL.AC.UK Subject: [ccp4bb] Suggestions for solving a structure with 8-10 copies per asymmetric unit Dear All, I have a question regarding solving a crystal structure by molecular replacement. It is a single protein with a molecular weight of 25.5 kDa. The cell dimension is rather big from the diffraction data ( 90.9 Å, 143.9 Å, 216.3Å, 90°, 90°, 90°). The possible space group is P212121. With such a big unit cell, we predicted that there are 8-10 molecules per asymmetric unit. We have a decent model with sequence similarity of 49%. I tried several times with Phaser search with the current model and had difficulty to find any clear solution. Has anyone seen such cases and any suggestions to solve the structure? Thanks! Jiyuan Ke, Ph.D. Research Scientist Van Andel Research Institute 333 Bostwick Ave NE Grand Rapids, MI 49503
