ATP synthase comprises a proton channel (Fo and a atPase(fu e The F, part consists of nine subunits of five types aBB3r68 e The knoblike F, portion is a hexamer of alternating a and B subunits(arranged like the segments of an orange), which sits atop the single rod-shaped y subunit e The Fo portion consists three types of subunits ab2C10-12 e The c subunits, each forming two transmembrane helices, form a donut-shaped ring in the plane of the membrane The F1 part consists of nine subunits of five types: a3b3 gde.  The knoblike F1 portion is a hexamer of alternating a and b subunits (arranged like the segments of an orange), which sits atop the single rod-shaped g subunit.  The Fo portion consists three types of subunits: ab2 c10-12.  The c subunits, each forming two transmembrane helices, form a donut-shaped ring in the plane of the membrane. ATP synthase comprises a proton channel (Fo ) and a ATPase (F1 )