Hi Ben, I would be very interested if you have a case where it makes a difference to do this. At one point I was convinced that it had been important when we were working on the structure of a Shiga-like toxin bound to trisaccharide (1bos), with four pentamers in the asymmetric unit. However, Pavel Afonine challenged me to show that the free set was less biased when chosen in shells than when chosen randomly, and even in that relatively extreme case I couldn’t see evidence of it. So it’s probably not worth the bother. Also, if you select the free set randomly, it’s distributed over the same resolutions as the working data, which arguably is important when you’re using it to calibrate the sigma(A) estimates for likelihood targets.
Best wishes, Randy > On 23 Jun 2025, at 12:35, Ben Bax <ben.d.v....@gmail.com> wrote: > > Hi, > How do you select R-free in shells with CCP4? > Thanks, Ben Bax > > ######################################################################## > > 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 http://www.jiscmail.ac.uk/CCP4BB, a > mailing list hosted by http://www.jiscmail.ac.uk/, terms & conditions are > available at https://www.jiscmail.ac.uk/policyandsecurity/ ----- Randy J. Read Department of Haematology, University of Cambridge Cambridge Institute for Medical Research Tel: +44 1223 336500 The Keith Peters Building Hills Road E-mail: rj...@cam.ac.uk Cambridge CB2 0XY, U.K. www-structmed.cimr.cam.ac.uk ######################################################################## 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/
