Hi Peer, I would definitively second Pierre's suggestion to use calculated data to simulate the self-rotation results. Do you see any density for the "lost" domain, or nothing at all? Could it be that this domain is flipped by 180° in part of the molecules, maybe due to a proteolytic cleavage?
Best, Heman -----Ursprüngliche Nachricht----- Von: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] Im Auftrag von Peer Mittl Gesendet: Mittwoch, 29. April 2015 14:00 An: CCP4BB@JISCMAIL.AC.UK Betreff: [ccp4bb] self-rotation in the absence of NCS We are working with a multi-domain protein crystallized in SG P6_5 with one molecule per asymmetric unit. The structure was refined at 2.00 A resolution with reasonable R-factors but unfortunately the domain we are most interested in seems to be disordered. Interestingly, the self-rotation function shows peaks on the kappa=180° plane (omega=90°, phi=19° (and every 30°)), with more than 50% origin peak height. Therefore, we are wondering if perhaps the space group assignment might be sub-optimal. Any explanations how these self-rotation peaks could occur and how we could extract meaningful information to resolve the disordered domain are welcome. Best regards, Peer P.S. Some additional information: pointless suggests SG P6_5, the data doesn't seem to be twinned (L-test), the refined part of the structure has no "internal symmetry" and refinement in P1 doesn't reveal the "lost" domain. -- **************************** Peer Mittl, PD Dr. Biochemisches Institut Universität Zürich Room 44M03 Winterthurer Strasse 190 CH-8057 Zürich Tel. +41-(0)44-6356559 Mobile +41-(0)76-2776566 Fax. +41-(0)44-6356834 Mail mi...@bioc.uzh.ch
