Hi Jeffrey, good question. Both twinning and NCS may couple reflections across free and working sets, and this should be avoided by proper selection - otherwise Rfree is biased towards Rwork. Selecting thin shells should be a good option, and can be done in SFTOOLS (or DATAMAN, or SHELXPRO).
How much does it matter? Actually I started to search the literature after reading your question, and expected that one of Z. Dauter's papers would enlighten me, but until a minute ago couldn't find the one(s) that I thought existed. But I found Fabiola et al., Acta Cryst. (2006). D62, 227–238 which is relevant for the coupling by NCS. Ah I just found Smietanska et al., Acta Cryst. (2020). D76, 653-667 where they indeed selected thin shells. Best wishes, Kay On Fri, 27 Aug 2021 13:24:05 +0000, Jeffrey B Bonanno <jeffrey.bona...@einsteinmed.org> wrote: >Hi Kay, > >Can you also comment on Rfree set selection? It seems thin shell might be >preferred in these cases? > >jbb > >Jeffrey B. Bonanno, Ph.D. >Department of Biochemistry >Albert Einstein College of Medicine >1300 Morris Park Avenue >Bronx, NY 10461 >off. 718-430-2452 fax. 718-430-8565 >email jeffrey.bona...@einsteinmed.org ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1 This message was issued to members of www.jiscmail.ac.uk/CCP4BB, a mailing list hosted by www.jiscmail.ac.uk, terms & conditions are available at https://www.jiscmail.ac.uk/policyandsecurity/
