Thermodynamic efficiency and mechanochemical coupling of F 1-ATPase

Shoichi Toyabe, Takahiro Watanabe-Nakayama, Tetsuaki Okamoto, Seishi Kudo, Eiro Muneyuki

Research output: Contribution to journalArticlepeer-review

128 Citations (Scopus)


F 1-ATPase is a nanosized biological energy transducer working as part of F oF 1-ATP synthase. Its rotary machinery transduces energy between chemical free energy and mechanical work and plays a central role in the cellular energy transduction by synthesizing most ATP in virtually all organisms. However, information about its energetics is limited compared to that of the reaction scheme. Actually, fundamental questions such as how efficiently F 1-ATPase transduces free energy remain unanswered. Here, we demonstrated reversible rotations of isolated F 1-ATPase in discrete 120° steps by precisely controlling both the external torque and the chemical potential of ATP hydrolysis as a model system of F oF 1- ATP synthase. We found that the maximum work performed by F 1-ATPase per 120° step is nearly equal to the thermodynamical maximum work that can be extracted from a single ATP hydrolysis under a broad range of conditions. Our results suggested a 100% free-energy transduction efficiency and a tight mechanochemical coupling of F 1-ATPase.

Original languageEnglish
Pages (from-to)17951-17956
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number44
Publication statusPublished - 2011 Nov 1


  • Electrorotation
  • Molecular motor
  • Nonequilibrium physics


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