Are you using CNS 1.2? This version has a robust bulk solvent model and
anisotropic correction
that is much improved compared to CNS 1.1. It is similarly robust as
that of Phenix (although
different in detail).
Axel Brunger
Van Den Berg, Bert wrote:
Hi all,
during refinement of our (membrane protein) structures, basically in
all cases the R/Rfree values depend a lot on the low resolution
cutoff. Putting the cutoff at lower res (20-50 A) results in
substantially higher R/Rfree values (sometimes few percent). For this
reason we mostly refine the data from the high-res limit down to 10A
or so. I have noticed that this occurs fairly often in the literature,
but I don't know if this is a membrane protein related issue or not.
Could it be that the bulk solvent model used in CNS (we refine
exclusively with CNS) does not model the situation with membrane
proteins, due to the presence of detergents? Or is it related to data
collection issues (low-res spots overloaded etc)? Anything else? What
could be done to overcome the problem, and to use all the data in
refinement?
Thanks, Bert
Bert van den Berg
University of Massachusetts Medical School
Program in Molecular Medicine
Biotech II, 373 Plantation Street, Suite 115
--
Axel T. Brunger
Investigator, Howard Hughes Medical Institute
Professor of Molecular and Cellular Physiology
Stanford University
Web: http://atb.slac.stanford.edu
Email: [EMAIL PROTECTED]
Phone: +1 650-736-1031
Fax: +1 650-745-1463
