Determine Pointgroup Symmetry for each residue.
For Details on the Molecular Symmetry Determination see:
T. Pilati & A. Forni, J.Appl.Cryst. (1998), 31, 503-504 & (2000), 33, 417.
For CSM (i.e. Continuous Symmetry Measure), see:
H. Zabrodsky et al. (1993) JACS, 115, 8 8278-8289.