Figure 4.

(Left) Ribbon drawings showing two views, at right angles, of the structure of the α₃β₃γ subunits of ECF₁ as seen in the present 4.4-Å resolution electron-density map. (Right) Electron micrographs of intact ECF₁F_O [reprinted with permission from S. Wilkens and R. A. Capaldi and reproduced with permission from ref. 7 (Copyright 1998, Nature). In the top view, the main connection between the α₃β₃ hexamer and the c-ring is assumed to be made by the γ and ɛ subunits (Fig. 1). There is also thought to be a second connection, at the extreme left of the figure, made by the two b subunits. In the bottom view, the particle is rotated roughly 90°.