Fig. 6: Brownian ratchet rotation of c12-ring by pmf.
From: Rotary mechanism of the prokaryotic Vo motor driven by proton motive force
A A schematic of the interface between the a-subunit and the c12-ring. The ring is surrounded by lipids, as shown here. B is a magnified view of the interface. C The rotation scheme of c12-ring. top: The protonation of c(Z)/E63 causes cleavage of the salt bridge with the Arg residues of the a-subunit. middle: The deprotonated c(O)/E63 is attracted to the Arg residues of the a-subunit by Coulombic interaction (red arrow). The Brownian motion of the protonated (hydrophobic) c(Y)/E63 and c(Z)/E63 is biased toward the membrane (black arrows). bottom: After a 30° rotation, c(O)/E63 forms a new salt bridge with the Arg residues. c(P)/E63 is deprotonated.
