    New chain ID            Original chain ID

7prs-pdb-bundle1.pdb:
           A                       DDD
           B                       EEE
           C                       FFF
           D                       GGG
           E                       HHH
           F                       III
           G                       JJJ
           H                       KKK
           I                       LLL
           J                       MMM
           K                       DaD
           L                       GaG
           M                       HaH
           N                       JaJ
