    New chain ID            Original chain ID

9s72_1-pdb-bundle1.pdb:
           A                         A
           B                         b
           C                         C
           D                         D
           E                         e
           F                         F
           G                         g
           H                         h
           I                         a
           J                         B
           K                         c
           L                         d
           M                         E
9s72_1-pdb-bundle2.pdb:
           A                         E
           B                         f
           C                         G
           D                         H
