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Hi Peer, The first thing I would suggest is calculating the self-rotation again but using the FC from the refined model, for comparaison. Then, if you don't see the same supplementary peaks, you can try to play with the integration radius and resolution range. This could give you some hint on the origin of these peaks. Best regards, Pierre ________________________________________ De : CCP4 bulletin board [[log in to unmask]] de la part de Peer Mittl [[log in to unmask]] Envoyé : mercredi 29 avril 2015 13:59 À : [log in to unmask] Objet : [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 [log in to unmask]