From: Axel Kohlmeyer (akohlmey_at_cmm.chem.upenn.edu)
Date: Mon Jan 12 2009 - 14:37:05 CST

On Mon, 12 Jan 2009, Alison Grinthal wrote:

AG> Hi - Sorry if this exists and I just didn't find it, but is there any VMD
AG> plugin that finds the centers of mass for separate groups of residues in a
AG> molecule and then calculates the distances between them? Many thanks.

alison,

you can implement this as a custom script very easily.
here is some kind of template (untested, so beware of typos):

set sel1 [atomselect top "<selection text for group 1>"
set sel2 [atomselect top "<selection text for group 2>"

set len [vecdist [measure center $sel1 weight mass] \
                 [measure center $sel2 weight mass] ]

cheers,
  axel.

AG>

-- 
=======================================================================
Axel Kohlmeyer   akohlmey_at_cmm.chem.upenn.edu   http://www.cmm.upenn.edu
   Center for Molecular Modeling   --   University of Pennsylvania
Department of Chemistry, 231 S.34th Street, Philadelphia, PA 19104-6323
tel: 1-215-898-1582,  fax: 1-215-573-6233,  office-tel: 1-215-898-5425
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If you make something idiot-proof, the universe creates a better idiot.