    New chain ID            Original chain ID

8u7z-pdb-bundle1.pdb:
           A                        B1
           B                        B2
           C                        B3
           D                        B4
           E                        B5
           F                        G1
           G                        G2
           H                        G3
           I                        G4
           J                        G5
           K                        K1
           L                        K2
           M                        K3
           N                        K4
           O                        K5
