Figure 7.

Increasing TM7b ST activity shifts TM8 toward the unconventional topology. Topology of polypeptides from plasmids S.gG.TM7b*.P (A) and S.gG.TM7b*-8.P (B). (A) Downward and upward arrows indicate full-length and PK-protected polypeptides, respectively. The uniform topology of chains is diagrammed. (B) Double and single arrows indicate double- and single-spanning chains, respectively. Topology of these two cohorts of chains is indicated. PK digestion of polypeptides yielded a 23-kDa, globin-reactive fragment in lane 2, which was clearly visible on longer exposure of the autoradiogram (our unpublished observations).