    New chain ID            Original chain ID

9squ_1-pdb-bundle1.pdb:
           A                         A
           B                         B
           C                         E
           D                         F
           E                         C
           F                         D
           G                         G
           H                         H
           I                         I
           J                         J
           K                         K
           L                         L
           M                         M
9squ_1-pdb-bundle2.pdb:
           A                         M
           B                         N
           C                         O
           D                         P
           E                         Q
           F                         R
           G                         S
           H                         T
           I                         U
           J                         V
           K                         W
           L                         X
           M                         Y
           N                         Z
9squ_1-pdb-bundle3.pdb:
           A                         Z
           B                         a
           C                         b
           D                         c
           E                         d
