Subject: Superimposing 2 Molecules

From: "C.F. Matta" <[email-masked]>
Date: Mon, 29 Nov 1999 19:29:51 -0500 (EST)

Hi everybody

        Is there a free (or inexpensive) software to superimpose a floppy
structure (F) on a rigid template structure (R).  The objective is to
obtain a geometry of (F) in a conformation that mimic (R) as closely as
possible (in a least square sense).

        One should be able to obtain the best superimposition of atoms of
(F)
to their equivalents in (R), by modifying the torsion angles of (F).

        Not all atoms in (F) have to have equivalent atoms in (R). Regions
of (F) that do not have equivalent atoms in (R) (but fall within 2 regions
that are  say FI and FII) should be allowed to twist in such a way as to
preserve the relative distances and orientations of FI and FII.

        Am I asking for too much and should consider writing the code
myself (in which case, any suggestions for algorithms/references)?

        Thank you very much. I will summarize your answers.

Cherif

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 Cherif F. Matta		  	tel. (905) 525-9140 ext. 22502
 Chemistry Department                   fax  (905) 522-2509
 McMaster University                      
 Hamilton, Ontario, CANADA L8S 4M1.
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