    New chain ID            Original chain ID

7b5i-pdb-bundle1.pdb:
           A                        AA
           B                        AB
           C                        AC
           D                        AD
           E                        AE
           F                        BA
           G                        BB
           H                        BC
           I                        BD
           J                        BE
           K                        CA
           L                        CB
           M                        CC
           N                        CD
           O                        CE
           P                        DA
           Q                        DB
           R                        DC
           S                        DD
           T                        DE
           U                        EA
           V                        EB
           W                        EC
           X                        ED
           Y                        EE
           Z                        FA
           a                        FB
           b                        FC
           c                        FD
           d                        FE
