Symmetry elements from XYZ

Sean Parkin sp at
Thu Apr 17 04:11:17 EST 1997

islam wrote:

> Given an orthogonal dataset of coordinates for 2 identical
> molecules is it possible to derive the symmetry operator relating
> them or determine if one exists ?

There is a bunch of stuff on this topic in old Acta Cryst. issues,
notably by Diamond and by Kearsley.  Bernhard Rupp and I recently
wrote a little FORTRAN program called PDBSUP that will superpose
two molecules.  They don't have to be exactly identical, but need
corresponding atoms.  It also gives a rmsd value for the fit.

You can get the program via ftp ( or from our
web site (

Some references are:

Diamond, R. (1988) Acta Cryst. A44, 211-216.
Kearsley, S.K. (1989) Acta Cryst. A45, 208-210.

hope this helps,  Sean

Dr. Sean Parkin
L-452, BBRP, LLNL, Livermore, CA., 94550
(510) 423-5427
sp at

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