The ATP-waiting conformation of rotating F1-ATPase revealed by single-pair fluorescence resonance energy transfer

AUTOR(ES)

Yasuda, Ryohei

FONTE

National Academy of Sciences

RESUMO

F1-ATPase is an ATP-driven rotary motor in which a rod-shaped γ subunit rotates inside a cylinder made of α3β3 subunits. To elucidate the conformations of rotating F1, we measured fluorescence resonance energy transfer (FRET) between a donor on one of the three βs and an acceptor on γ in single F1 molecules. The yield of FRET changed stepwise at low ATP concentrations, reflecting the stepwise rotation of γ. In the ATP-waiting state, the FRET yields indicated a γ position ≈40° counterclockwise (= direction of rotation) from that in the crystal structures of mitochondrial F1, suggesting that the crystal structures mimic a metastable state before product release.

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