Refinement in CNS

Joe Krahn krahn at niehs.nih.gov
Thu Mar 25 15:02:14 EST 1999


Given a good starting structure, 3.0A data can do quite well.
Individual Bs might be OK if you keep strong bonded-B restraints.
I would try grouped B refinement starting from the 2.4A Bs.
Grouped B's will shift each set of Bs without setting them to a
single value.  This way, you're keeping some of the information
from the refined 2.4A structure.

I'm surprised that the working R went up; this means that the
X-ray data isn't pushing hard enough. Maybe you need to
update WA.

You might also try muti-fragment rigid body to give it a better
start.  I make a loop to chop the protein into sequential
10 residue segments and rigid body refine all of the groups.

Joe Krahn



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