Something else to consider is what is your space group ? P212121 but truly P21 with twinning fraction close to 0.5 ? That's one of my recent cases. 1.9 Å data beautifully refined & built but the Rwork/Rfree gap was 13 percent. After changing the space group and applying the twin law the gap is 3 percent 18.4 and 21.3
Jürgen - Jürgen Bosch Johns Hopkins Bloomberg School of Public Health Department of Biochemistry & Molecular Biology Johns Hopkins Malaria Research Institute 615 North Wolfe Street, W8708 Baltimore, MD 21205 Phone: +1-410-614-4742 Lab: +1-410-614-4894 Fax: +1-410-955-3655 http://web.mac.com/bosch_lab/ On Jul 8, 2010, at 1:17 AM, Sampath Natarajan wrote: > Dear all, > > I have a question about the R free value. I refined a structure with 2A > resolution. After model building and restraint refinement using Refmac > program, the average B factor was around 50 for all atoms. The R/Rfree were > around 22/34. Then used the TLS refinement choosing entire molecule. Then > R/Rfree reduced as 20/32. But the average B factor was reduced as 30. The > R/Rfree difference is about 12% in final refinement. I feel it is > significantly higher. > > Could any one suggest me to reduce the Rfree value more? or is it good to > submit the data in the PDB database with this 12% difference? > > Thanks for the suggestions. > > Sincerely, > Sampath N
