    New chain ID            Original chain ID

7zs5-pdb-bundle1.pdb:
           A                         1
           B                         3
           C                         4
           D                         A
           E                         2
           F                        BA
           G                        BB
           H                        BC
           I                        BD
           J                        BE
           K                        BF
           L                        BG
           M                        BH
           N                        BI
           O                        BJ
           P                        BL
           Q                        BM

7zs5-pdb-bundle2.pdb:
           A                        BN
           B                        BO
           C                        BP
           D                        BQ
           E                        BR
           F                        BS
           G                        BT
           H                        BU
           I                        BV
           J                        BW
           K                        BX
           L                        BY
           M                        BZ
           N                        Ba
           O                        Bb
           P                        Bc
           Q                        Bd
           R                        Be
           S                        Bf
           T                        Bg
           U                        Bh
           V                        Bi
           W                        Bj
           X                        Bk
           Y                        Bl
           Z                        Bm
           a                        Bn
           b                        BK
           c                         B
