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 pat.loll@drexelmed.edu
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: phenixbb-bounces@phenix-online.org [phenixbb-bounces@phenix-online.org] on behalf of Patrick Loll [pat.loll@drexel.edu] 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 pat.loll@drexelmed.edu _______________________________________________ phenixbb mailing list phenixbb@phenix-online.org http://phenix-online.org/mailman/listinfo/phenixbb
IMHO. if you have P622 apparent symmetry, your true symmetry could be either P6, P321, P312, or if you are unlucky, it is P3 and there are 4 twin domains. So the others are possibly right in suggesting P1 for twinning tests. BW, Gabor On Apr 19 2012, Patrick Loll wrote:
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The effects of twinning on the intensity distributions should be seen in even the highest point group. However, there won't be twin laws to test for twinning (and hence twin fraction estimation). For a more complete analysis looking at the data processed in the lower symmetry (P6 or below) would be better. On Apr 20, 2012, at 8:42 AM, wtempel wrote:
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participants (6)
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Gabor Bunkoczi -
Patrick Loll -
Paul Adams -
Ralf Grosse-Kunstleve -
Terwilliger, Thomas C -
wtempel