    New chain ID            Original chain ID

4v4z-pdb-bundle1.pdb:
           A                        AA
           B                        AC
           C                        AD
           D                        A1
           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                        AU
           V                        AV
           W                        AW
           X                        AX

4v4z-pdb-bundle2.pdb:
           A                        BA
           B                        BB
           C                        BC
           D                        BD
           E                        BE
           F                        BF
           G                        BG
           H                        BH
           I                        BK
           J                        BL
           K                        BM
           L                        BN
           M                        BO
           N                        BP
           O                        BQ
           P                        BR
           Q                        BS
           R                        BT
           S                        BU
           T                        BV
           U                        BW
           V                        BX
           W                        BY
           X                        BZ
           Y                        B1
           Z                        B2
           a                        B3
           b                        B4
           c                        B5
           d                        B6
           e                        B7
           f                        B8
