so reading a pdb file with multiple chains, IMP changes the residues
indexes to have sequential residue indexes.
so imagine 3 chains A from 1 to 10, B from 1 to 10 and C from 1 to 10
reading into IMP we get:
A from 1 to 10
B from 11 to 20
C from 21 to 30
this really messes up stuff ....
is there a special reason for that ?