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<DIV><FONT face=Arial size=2><FONT face="Times New Roman" size=3>Dear gmx'ers,
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<P>I am trying to use 7 spin relaxation NMR derived distance restraints between
atoms of a small organic molecule (substrate) and a protein to refine a
substrate-enzyme complex with MD. As a starting structure, I use a automaticaly
docked substrate pose in the protein binding pocket which is more or less in
agreement with these distance restraints. However, as the substrate and
the protein are not considered as one molecule, the distance restraints
are 'heavily violated' (31 nm!) as a result of the fact that the substrate is
'placed outside' the protein ('placed outside the box'), and the run crashes
immediately.
<P>I want to solve this problem by defining either one 'connection bond' or one
'harmonic potential bond' (with a force constant of "0") between the substrate
and the protein (in addition to the distance restraints), because I do not want
to turn these bonds into constraints, and I do not want to define a
'chemical' bond between the protein and the substrate. Which bond type should I
use?
<P>With kind regards and thanking you in advance,
<P>Chris <BR> <BR> <PRE>--
C. de Graaf, MSc
LACDR - Division of Molecular Toxicology
Department of Pharmacochemistry,
Vrije Universiteit,
De Boelelaan 1083, 1081 HV Amsterdam
Tel. (31) 020-4447608
Fax. (31) 020-4447610
email: degraaf@few.vu.nl</PRE> </FONT></DIV></BODY></HTML>