covalent bond between symmetry related halves of a spermine molecule

[Sjoerd van den Worm]

Build the whole spermine molecule and use the following to prevent X-plor from
calculating the vdW and elec energies of interactions with the symmetry related
partner(s), i.e. itself:

        constraints
          inter=(not segid S) (all)          
          weights * 1. end
          inter=(segid S) (all)          
          weights * 1. pvdw 0. pele 0. end
        end  {constraints}

where S is the segid of spermine. X-plor *will* give a long (annoying) list of
short contacts, but this doesn't affect refinement.

Good luck,
Sjoerd