    New chain ID            Original chain ID

3j9l-pdb-bundle1.pdb:
           A                         A
           C                         C
           D                         D
           E                         E
           F                         F
           G                         G
           H                         H
           I                         I
           J                         J
           K                         K
           L                         L
           M                         M
           N                         N
           O                         O

3j9l-pdb-bundle2.pdb:
           P                         P
           Q                         Q
