Figure3. The molecular structure of the F1 subunit of the ATP Synthase complex found in the bacterial outer membrane. The F1 complex has five parts, here labeled a, b, g, d and e. Three each of a and b subunits are associated in a hexamer with each a unit alternating with a b unit. The hexamer surrounds a single g unit that has a complex coiled region for insertion into the c ring (rotor) of the F0 complex. (see figure 4). The d subunit of the F1 contacts the b protein of the F0 complex, acting as a stator. The function of the e subunit is not well understood, but it may serve to anchor the g protein to the "c" subunit of the F0 complex.