Hi everyone,
I have a dataset that's been giving me some trouble and wanted to get your ideas on the best way to proceed. The data extend to ~2.6 Å and scale integrate/scale well in P622. According to Pointless, the symmetry is either P622 or P6322, however, neither Molrep norm Phaser finds molecular replacement solutions in these space groups. If I run Phaser and let it check all other space groups it finds a solution in P6122, but I can only refine it to an Rfree value of ~35%. The data also scales well in P3 and P6 and I get molecular replacement solutions in space groups of either P31 or P61. However, the Refinement again stalls at an Rfree value of ~35%. I tried adding twin refinement in Refmac and it seems to be helping; The R/Rfree values dropped to 20.9/27.3 and the map appears much better compared to the previous refinements. The refined twin fractions are 0.26, 0.24, 0.24 and 0.25. Am I doing something wrong with the refinement or is this a legitimate way to treat the data. Thank you in advance for your help.
