    New chain ID            Original chain ID

9ygy-pdb-bundle1.pdb:
           A                         5
           B                         6
           C                         7
           D                         8
           E                         A
           F                         B
           G                         D
           H                         E
           I                         F
           J                         G
           K                         I
           L                         J
           M                        K2
           N                        L2
           O                        M2
           P                         N
           Q                        N2
           R                        O2
           S                        P2
           T                        y3
           U                         K
           V                         C
           W                         H
           X                         L
