    New chain ID            Original chain ID

26ir_1-pdb-bundle1.pdb:
           A                         A
           B                         B
26ir_1-pdb-bundle2.pdb:
           A                         B
           B                         C
           C                         D
26ir_1-pdb-bundle3.pdb:
           A                         D
           B                         G
           C                         H
           D                         I
           E                         J
