Hello, with a=b in both cases, I am sure you have considered tetragonal. I remember convincing myself something was F222 when it actually was I422.
Best wishes, Jon Cooper. jon.b.coo...@protonmail.com Sent from Proton Mail Android -------- Original Message -------- On 08/07/2024 12:07, Nichols, Charlie wrote: > Hi, > > I am trying to recapitulate a published crystallisation system. The published > crystal form is P212121 approx cell dimensions 80, 80, 120 // 90, 90, 90 with > one trimer in the ASU > > We did not get any crystals in the published conditions but have found a new > condition giving data to a much higher resolution than the published one but > there is a problem… > > New crystal form is F222 with approx cell dimensions 40, 40, 120 // 90, 90, > 90 – this cell is too small to fit one monomer let alone one trimer. > > The prep is remarkably clean and there is a high volume of crystals in the > drop so unlikely to be a contaminant. I have tried molrep with individual > domains in case there has been degradation during crystallisation but this > does not look at all promising. > > I am wondering, given the almost exact halving of the a/b cell dimensions and > almost exact equivalence of the c cell dimension, whether this is a > particularly egregious form of twinning where the twin is three 2-fold screw > axes to cause an apparent reduction in the unit cell. > > Is there a way to expand the data from the current 40, 40, 120 // 90, 90, 90 > unit cell to the larger ‘super-cell’ 80, 80, 120 // 90, 90, 90 with four > copies of the data to then attempt either molep or just twin refinement with > the original published model? > > Any comments / help appreciated – NB: I can’t share the actual data or even > the target as they are confidential client data… > > Thanks, take care, > > Charlie Nichols > > --------------------------------------------------------------- > > To unsubscribe from the CCP4BB list, click the following link: > https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1 ######################################################################## 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/
