    New chain ID            Original chain ID

8p4t-pdb-bundle1.pdb:
           A                         A
           B                         a
           C                        SA
           D                         B
           E                         C
           F                        SB
           G                        SC
           H                         b
           I                         c
           J                         D
           K                         E
           L                         F
           M                         G
           N                         H
           O                         I
           P                         J
           Q                         K
           R                         L
