    New chain ID            Original chain ID

9t4r-pdb-bundle1.pdb:
           0                         0
           X                         X
           1                         1
           Z                         Z
           2                         2
           a                         a
           3                         3

9t4r-pdb-bundle2.pdb:
           b                         b
           4                         4
           c                         c
           A                         A
           d                         d
           B                         B
           e                         e
           C                         C
           f                         f
           D                         D
           g                         g
           E                         E
           j                         j
           F                         F
           k                         k
           G                         G
           l                         l
           H                         H
           m                         m
           I                         I
           n                         n
           J                         J
           o                         o
           K                         K
           p                         p
           L                         L
           q                         q
           M                         M
           r                         r
           N                         N
           s                         s
           O                         O

9t4r-pdb-bundle3.pdb:
           t                         t
           P                         P
           u                         u
           Q                         Q
           v                         v
           R                         R
           w                         w
           S                         S
           x                         x
           T                         T
           y                         y
           U                         U
           z                         z
