    New chain ID            Original chain ID

9y6u-pdb-bundle1.pdb:
           A                        IA
           B                        IB
           C                        IC
           D                        ID
           E                        IE
           F                        IF
           G                        IG
           H                        IH
           I                        II
           J                        IJ
           K                        IK
           L                        IL
           M                        IM
           N                        IN
           O                        IO
           P                        IP
           Q                        IQ
           R                        IR
           S                        IS
           T                        IT
           U                        IU
           V                        IV
           W                        IW
           X                        IX
