Dear Rohit, I wouldn’t judge a structure just by the Rwork and Rfree values, but also by the validation and other statistics (bond lengths, angles, Ramachandran plot, map quality, fit to map, average B values). If these are all ok, you should be able to “get away with” an Rfree of 33%. In your email you state that you have already made a significant effort in different refinement strategies, so perhaps there is no improvement to be made there. The reason for the high-ish Rfree could be that the data is not so good, and reprocessing might help. Although the most likely outcome is that you can’t significantly improve it, but at least trying will put your mind more at ease. In the end, the only way to improve the structure, and R-factors, may be to grow a better crystal, cryo-protect better and/or collect better data - this particular crystal may just have some kind of disorder.
Greetings, Mark J van Raaij Dpto de Estructura de Macromoleculas Centro Nacional de Biotecnologia - CSIC calle Darwin 3 E-28049 Madrid, Spain tel. (+34) 91 585 4616 http://wwwuser.cnb.csic.es/~mjvanraaij > On 14 Dec 2016, at 16:02, rohit kumar <rohit...@gmail.com> wrote: > > Dear All, > > I am solving a data of 2.5 A (C121 space group). Right now the R/Rfree values > are 26/33, after many cycles of refinements (With or With out water) the > R/Rfree values still same. Zanuda suggests that the space group seems to be > correct and the model is looking fine in coot. > Some one suggest what is the main problem. > Should I again process my data? And what is the best way to fine right space > group (If problem with space group). > Please tell me if you need any information regarding may data. > > -- > WITH REGARDS > Rohit Kumar Singh > Lab. no. 430, > P.I. Dr. S. Gourinath, > School of Life Sciences, > Jawaharlal Nehru University > New Delhi -110067
