    New chain ID            Original chain ID

6y67-pdb-bundle1.pdb:
           A                       AAA
           B                       BBB
           C                       CCC
           D                       DDD
           E                       EEE
           F                       FFF
           G                       GGG
           H                       HHH
           I                       III
           J                       JJJ
           K                       KKK
           L                       LLL
           M                       MMM
           N                       NNN
           O                       OOO
           P                       PPP
           Q                       QQQ
           R                       RRR
           S                       SSS
           T                       TTT
           U                       UUU
           V                       VVV
           W                       WWW
           X                       XXX
           Y                       YYY
           Z                       ZZZ
           a                       aaa
           b                       bbb
           c                       ccc
           d                       ddd
