Dear ccp4 bulletin board I just have a slight concern regarding my Rwork Rfree difference. I have a structure that I have solved. I am reasonably content that it is complete because it has refined well, it no longer has bad geometries and contacts and all the rotamers, ramachandra, bond lengths etc are good. It gives favourable scores on molprobity and procheck. My only concern is the R factor difference. The resolution of the structure is 2.3A. The R factor is 0.24 after refinement but the Rfree is 0.33 which seems to me to be rather high. Should I be concerned?
During refinement Rfree only drops from about 0.36 to 0.33 while the R factor drops from 0.31 to 0.24.. I have removed automatic weighting in refmac in order to constrain my bond lengths and angles during a couple of rounds of refinement. This did not have any effect on the R factors, however. I am fairly content that the space group I have chosen is correct so I am not sure what else could cause the big difference in R factors? There is no twinning. Can I be satisfied that my structure is correct despite the high R free or should I be doing other checks/ trying other things before I can submit this structure? Thank you for any help Careina
