    New chain ID            Original chain ID

4v68-pdb-bundle1.pdb:
           A                        AA
           B                        AB
           C                        AD
           D                        AE
           E                        AF
           F                        AH
           G                        AK
           H                        AL
           I                        AO
           J                        AP
           K                        AQ
           L                        AR
           M                        AT
           N                        AC
           O                        AG
           P                        AI
           Q                        AJ
           R                        AM
           S                        AN
           T                        AS
           U                        AU
           V                        AV
           W                        AX
           X                        AW
           Y                        AY
           Z                        A0
           a                        AZ
           b                        B0
           c                        B1
           d                        B2
           e                        B3
           f                        B4
           g                        B5
           h                        B6
           i                        B7
           j                        B8
           k                        B9

4v68-pdb-bundle2.pdb:
           A                        BA
           B                        BB
           C                        BC
           D                        BD
           E                        BE
           F                        BF
           G                        BG
           H                        BH
           I                        BI
           J                        BL
           K                        BN
           L                        BO
           M                        BP
           N                        BQ
           O                        BR
           P                        BS
           Q                        BT
           R                        BU
           S                        BV
           T                        BW
           U                        BX
           V                        BY
           W                        BZ
