    New chain ID            Original chain ID

6v3d-pdb-bundle1.pdb:
           A                         0
           B                         1
           C                         2
           D                         3
           E                       AN1
           F                         B
           G                         C
           H                         D
           I                         E
           J                         F
           K                         G
           L                         H
           M                         I
           N                         J
           O                         K
           P                         L
           Q                         M
           R                         N
           S                         O
           T                         P
           U                         Q
           V                         R
           W                         S
           X                         T
           Y                         U
           Z                         V
           a                         W
           b                         X
           c                         Y
           d                         Z
