Fig. 6
From: Structural basis for energy transduction by respiratory alternative complex III
Proton pathways. a ActC proton-conducting half-channels. The cytoplasmic half-channel (TMHs 2–5) consists of residues Asp197, Arg196, Asp191, Arg119, Glu450, Arg114, Glu122, Ser103, Thr100, Thr125, Ser180, Tyr176, His97, and His247. The periplasmic half-channel (TMHs 6–9) includes residues Arg395, Glu394, Tyr270, Tyr323, Glu326, and Glu338. The approximate position of the quinol pocket is indicated (QH2). b ActF proton-conducting half-channels. Cytoplasmic (TMHs 2–5) and periplasmic (TMHs 6–9) proton-conducting half-channels of ActF include residues Asp184, Arg100, Ser180, Glu103, His88, Ser80, Ser238, His355, Asp358, Tyr233, Tyr290, Arg308, and Glu301. The four-helix bundles are shown in light blue (TMHs 2–5) and yellow (TMHs 6–9). Note that density for aspartate and glutamate residues is not visible and their side chains have been modeled
