Subject: DGEOM questions for conf anal...

From: [email-masked] (Joe M Leonard)
Date: Wed, 17 Nov 1993 21:34:47 -0500

Folks,
	I'm trying to use DGEOM ('89-'90 vintage) for conformational
analysis, but am interested in having phenyl/aromatic groups remain
unaltered during the calculations.  I've tried making them their own
residues (while the rest of the molecule's the "other" residue") and
using the RIGID global keyword for the aromatic residues, but the
various rings distort during the calculation.  Am I missing something
here?  Should I also insert  PLANE local constraints for things to work
(I'm uniquely naming atoms in each aromatic residue, but the names are shared
between residues).

	I realize that the rings will flatten out when some form of energy
function's applied to the resulting structures, but I'm interested in 
trying to keep the number of opt cycles to a minimum (and since the
initial phenyl group geoms are ok...).  Have there been changes to newer
versions that make this an easier process (or have changes been made that I
should be aware of)?

	I'd appreciate learning from others who have solved this problem...
If any of the authors have comments, I'd REALLY appreciate hearing from them.

Joe Leonard
[email-masked]