Figure 1.

Sketch showing the presumed overall structure of the E. coli F₁F_O-ATP synthase. The figure is based on electron microscopic, x-ray, and crosslinking studies of the E. coli and related enzymes (see text). The F₁ part (Upper) includes the hexagonal ring of alternating α and β subunits that enclose part of γ. The F_O part includes the c subunits, which form a ring at the bottom and also contact part of γ (see text). The shape of γ is in part suggested by the present work. No information is provided regarding ɛ, which is therefore drawn with a broken line.