alternate conformations - non side chain case

Lionel Mourey mourey at ipbs.fr
Wed Mar 25 04:16:34 EST 1998


Dear all,

I am wondering if somebody would like to share his own experience in
dealing with alternate conformations. 

In the course of the crystal structure refinement of a protein
covalently modified by a small molecule, it seems that the latter adopts
alternate conformations which account for electron density and can
easily be built by playing around dihedral angles. Then I thought that
everything could be easily handled in X-PLOR, in the same way as for
alternate side chain conformations (and indeed there are some in this
structure that refined pretty well), i.e. using the "duplicate..." and
"constraints inter ..." statements. Alas, refinement instead pushed the
two conformers away and out of density as to minimize steric hindrance
of too close atoms while preserving bonds lengths (thus, in their new
position, the two conformers are still bound to the molecule).

Any help will be grately appreciated.

Lionel

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Lionel MOUREY		
Groupe de Cristallographie Biologique
IPBS-CNRS			
205, route de Narbonne 	      Tel (33 or 0) 5 61 17 54 45 
31077 TOULOUSE CEDEX	      Fax (33 or 0) 5 61 17 54 48   
France	                      e-mail   mourey at ipbs.fr 

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