help: packing energy

[yangj at skyfox.usask.ca]

Hello, everyone, I have a problem that I need your help.  Could anybody tell
me which program can calculate the packing energy between a domain of a molecule
with symmetry-related molecules with pdb coordinates?  I thank you in advance 
for your help.
Sincerely,
Jian Yang
Department of Chemistry
University of Saskatchewan
Saskatoon, Saskatchewan
Canada S7N 5C9
Tel: (306) 966-4366
Email: yangj at sask.usask.ca