    New chain ID            Original chain ID

9ss2-pdb-bundle1.pdb:
           A                        AA
           B                        AB
           C                        AC
           D                        AD
           E                        AE
           F                        AF
           G                        AG
           H                        AH
           I                        AI
           J                        AJ
           K                        AK
           L                        AL
           M                        AM
           N                        AN
           O                        AO
           P                        AP
           Q                        AQ
           R                        AR
           S                        AS
           T                        AT
           U                        D1
           V                        F1
           W                        F3
