    New chain ID            Original chain ID

5gak-pdb-bundle1.pdb:
           1                         1
           X                         X
           3                         3
           Y                         Y
           4                         4
           Z                         Z
           A                         A
           a                         a
           B                         B
           b                         b
           C                         C
           c                         c
           D                         D
           d                         d
           E                         E
           e                         e
           F                         F
           f                         f
           G                         G
           g                         g
           H                         H
           h                         h
           I                         I

5gak-pdb-bundle2.pdb:
           i                         i
           J                         J
           j                         j
           K                         K
           k                         k
           L                         L
           l                         l
           M                         M
           m                         m
           N                         N
           n                         n
           O                         O
           o                         o
           P                         P
           p                         p
           Q                         Q
           q                         q
           R                         R
           r                         r
           S                         S
           s                         s
           T                         T
           U                         U
           V                         V
           W                         W
           z                         z
