Hi Pat, As Ralf says, P6 or P1. I think if the data merges well in both P622 and P6 then you are going to get very similar twinning statistics in the two space groups. This would not be true if the data merged poorly in P622; in that case merging to P622 it would make it look twinned. All the best, Tom T ________________________________________ From: [email protected] [[email protected]] on behalf of Patrick Loll [[email protected]] Sent: Thursday, April 19, 2012 10:45 AM To: PHENIX user mailing list Subject: [phenixbb] twinning question Dumb question here: When one runs the various twinning tests (e.g. phenix.xtriage), is one meant to use data processed in the higher symmetry SG, or the lower symmetry SG? A concrete example: I can process a data set in a 622 point group w/ reasonable merging statistics, but an abnormally low solvent content raises my suspicions. So do I process as P6, and submit these data to the twinning test? Or do I submit the data processed as P622? Pat --------------------------------------------------------------------------------------- Patrick J. Loll, Ph. D. Professor of Biochemistry & Molecular Biology Director, Biochemistry Graduate Program Drexel University College of Medicine Room 10-102 New College Building 245 N. 15th St., Mailstop 497 Philadelphia, PA 19102-1192 USA (215) 762-7706 [email protected] _______________________________________________ phenixbb mailing list [email protected] http://phenix-online.org/mailman/listinfo/phenixbb

Did I infer correctly from Padilla & Yeates (2002) Acta Cryst D59:1124-30 that the L-test could indicate twinning even if data were merged in the apparent higher-symmetry point group? Wolfram Tempel On Thu, Apr 19, 2012 at 12:45 PM, Patrick Loll wrote:

Dumb question here: When one runs the various twinning tests (e.g. phenix.xtriage), is one meant to use data processed in the higher symmetry SG, or the lower symmetry SG?

A concrete example: I can process a data set in a 622 point group w/ reasonable merging statistics, but an abnormally low solvent content raises my suspicions. So do I process as P6, and submit these data to the twinning test? Or do I submit the data processed as P622?

Pat

--------------------------------------------------------------------------------------- Patrick J. Loll, Ph. D. Professor of Biochemistry & Molecular Biology Director, Biochemistry Graduate Program Drexel University College of Medicine Room 10-102 New College Building 245 N. 15th St., Mailstop 497 Philadelphia, PA 19102-1192 USA

(215) 762-7706 [email protected]

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