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Publication Abstract from PubMed

ATP synthases play a crucial role in energy production by utilizing the proton motive force (pmf) across the membrane to rotate their membrane-embedded rotor c-ring, and thus driving ATP synthesis in the hydrophilic catalytic hexamer. However, the mechanism of how pmf converts into c-ring rotation remains unclear. This study presents a 2.8 A cryo-EM structure of the V(o) domain of V/A-ATPase from Thermus thermophilus, revealing precise orientations of glutamate (Glu) residues in the c(12)-ring. Three Glu residues face a water channel, with one forming a salt bridge with the Arginine in the stator (a/Arg). Molecular dynamics (MD) simulations show that protonation of specific Glu residues triggers unidirectional Brownian motion of the c(12)-ring towards ATP synthesis. When the key Glu remains unprotonated, the salt bridge persists, blocking rotation. These findings suggest that asymmetry in the protonation of c/Glu residues biases c(12)-ring movement, facilitating rotation and ATP synthesis.

Rotary mechanism of the prokaryotic V(o) motor driven by proton motive force.,Kishikawa JI, Nishida Y, Nakano A, Kato T, Mitsuoka K, Okazaki KI, Yokoyama K Nat Commun. 2024 Nov 20;15(1):9883. doi: 10.1038/s41467-024-53504-x. PMID:39567487^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.