    New chain ID            Original chain ID

9r9i_1-pdb-bundle1.pdb:
           A                         O
           B                         P
           C                         Q
           D                         R
           E                         S
           F                         T
           G                         U
           H                         V
           I                         W
           J                         X
           K                         Y
           L                         Z
           M                         a
           N                         b
9r9i_1-pdb-bundle2.pdb:
           A                         b
           B                         c
           C                         d
           D                         e
           E                         f
