The twin fraction can vary during data collection - if the beam is smaller than the crystal For example you could have crystals which are like two very short ends of pencils - with flat ends together (in your case these might pencils could be in P3) In some orientations you could have the beam going through only one pencil (not twinned) and some orientations going through both pencils ( 50:50 twin). This is not yet properly handled in the data processing.
On 29 Mar 2022, at 09:39, Nicholas Keep <n.k...@bbk.ac.uk> wrote: Just double checking that Refmac automatically handles twinning without the need for a keyword or a box click in i2. I have a crystal in P32 21 that gives poor Rfactors and maps (Rfree mid 40s) from what should be an excellent model. I have reprocessed in P32, P1 and C2 but all give similar results so it appears not to be hidden twinning. There is no need to click a box or enter a keyword for this to be a check for twinning ? There is severe anisotropy and a few other problems flagged up in iSPYB so there may be more complex problems than twinning with these crystals Best wishes Nick -- Prof Nicholas H. Keep Emeritus Professor of Biomolecular Science Crystallography, Institute for Structural and Molecular Biology, Department of Biological Sciences Birkbeck, University of London, Malet Street, Bloomsbury LONDON WC1E 7HX Dept email n.k...@bbk.ac.uk Telephone 020-3926-3475 (Will contact me at home if working as well as my office) ######################################################################## 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/ ######################################################################## 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/
