Besides possibilities pointed, I would ask if your are using undue NCS
restraints, id est, between "rotamers" which are genuinely "different".
Anyway, at 1.8 A resolution, one should check the adequateness of using
NCS restraints.
J
Hi,
I'm working with a 1.8 A structure with Coot and Refmac, and there
are many sidechain rotamers that show very clear difference density
peaks for setting their correct positions. However, Refmac
continuously moves the rotamers back into negative density peaks.
It's really quite silly because often there is an obvious positive
density peak near to a negative density peak.
I have tried using automatic geometry weighting and manually setting
the weighting term to a very tight 0.025, but each has no effect. I
have also tried increasing the torsion angle restraint term to 2.0
but this also has no effect.
Does anyone have any suggestions? Is there any way to "fix" atom
positions for Refmac?
Thanks in advance,
~
Peter J Stogios, Ph.D.
Postdoctoral Research Fellow
e: [email protected]
p: 416-978-4033
w: http://www.uhnres.utoronto.ca/centres/proteomics/
Structural Proteomics in Toronto Research Group, University Health Network
C.H. Best Institute
112 College Street, Room 70
Toronto, Ontario, Canada M5G 1L6
