[gmx-users] ASP improper dihedral opls

[Ilya Chorny]

Hello,

I have been running some simulation with an ethylacetate using  parameters
from aspartate in the OPLS force field. With the current OPLS parameters the
oxygens on the acetyl group point into the plane. I then increased the force
constant on the C O O C  improper dihedral by a factor of ten. The oxygens
then became planar but pointed in the oppisite direction. I then flipped the
improper dihedral angle from 180 to 0.0 and it began to look ok. I just
wanted people to know about this in case their carbonyls looked funny in
their protein simulations.

Cheers,

Ilya

-- 
Ilya Chorny Ph.D.
Alfred P. Sloan Foundation Postdoctoral Fellow
Department of Pharmaceutical Chemistry
University of California, San Francisco
San Francisco, CA 94143
Direct: (408)887-8496
Work: (415)476-6875