Fig. 3.
Control of the ISP-ED motion switch and the proposed mechanism for electron bifurcation at the Qo pocket. The structural components necessary for the control of ISP conformational switch are illustrated in this cartoon rendition of the Qo pocket. The PEWY motif and cd1 helix in gray represent a native (Rest) configuration. The ISP in yellow and magenta are of oxidized and reduced form, respectively. The PEWY in blue stands for the open configuration with a bound Qo site inhibitor. The cd1 helix in red symbolizes the conformation (On/+) in the presence of a Pf inhibitor occupying the distal site (pink), and the cd1 helix in green shows the conformation (Off/−) when a Pm inhibitor is taking the proximal site (purple). Cyt c1 and heme bL are also shown.