Perfect chemomechanical coupling of F o F 1 -ATP synthase

Significance Peter D. Mitchell, a Nobel awardee in 1978, proposed that F o F 1 -ATP synthase converts energy between electrochemical potential of H + across biological membrane ( Δ μ ∼ H + ), which is established by respiratory chain complexes, and chemical potential of adenine nucleotide [ΔG (ATP) ]. However, the efficiency of the energy conversion has been a matter of debate for over 50 years. In this study, with a highly reproducible analytical system using F o F 1 -ATP synthase from thermophilic Bacillus , apparently perfect energy conversion was observed. Mitchell’s prediction thus has quantitative evidence.