conformations

Joe Krahn krahn at niehs.nih.gov
Wed Dec 30 22:16:23 EST 1998


Is there really any notable structural difference between the keto and
enol
forms?  Differences between single/double bond lengths are so small,
it's
probably not worth it unless you have very high resolution.

To do so, look at examples for multiple conformations.  You need
a few "constraints interactions" statements to keep thw two forms
from interacting with each other.  You can refine grouped occupancies
for the two substrate forms with "optimize group q=()..." but you
can't constrain the sum to be 1 or <=1.  Also, with B and occupoancies
correlated, I usually adjust the average B's of the two conformations
to be equal before doing occupancy refinement.

Joe Krahn

Jodi Lubetsky wrote:
> 
> dear users,
> 
> I am refining a structure of an enzyme complexed to its substrate/product.  THe
> enzyme catalyzes the conversion between the keto and enol forms, and both fit
> into my SA-omit map electron density.  I was wondering how i would go about
> further refinement including both forms in my coordinates.  Additionally, is
> there a way to also refine the occupancies of both forms?
> 
> thanks in advance,
> jodi



More information about the X-plor mailing list