    New chain ID            Original chain ID

7wfe-pdb-bundle1.pdb:
           A                        BA
           B                        BB
           C                        BC
           D                        BD
           E                        BE
           F                        BF
           G                        BG
           H                        BH
           I                        BI
           J                        BJ
           K                        BK
           L                        BL
           M                        B1
           N                        B2
           O                        B3
           P                        B5
