36 degree step size of proton-driven c-ring rotation in FoF1-ATP synthase

TL;DR

This study demonstrates that the proton-driven rotation of the c-ring in FoF1-ATP synthase occurs in 36-degree steps, aligning with theoretical models, using single-molecule fluorescence resonance energy transfer.

Contribution

It provides direct experimental evidence of 36-degree stepping in c-ring rotation, confirming predictions of Fo motor models.

Findings

Proton-driven c-ring rotation occurs in 36-degree steps.

Single-molecule FRET effectively reveals rotational steps.

Results support theoretical models of Fo motor rotation.

Abstract

Synthesis of the biological "energy currency molecule" adenosine triphosphate ATP is accomplished by FoF1-ATP synthase. In the plasma membrane of Escherichia coli, proton-driven rotation of a ring of 10 c subunits in the Fo motor powers catalysis in the F1 motor. While F1 uses 120 degree stepping, Fo models predict a step-by-step rotation of c subunits 36 degree at a time, which is here demonstrated by single-molecule fluorescence resonance energy transfer.