TY - JOUR
T1 - Thermodynamic efficiency and mechanochemical coupling of F 1-ATPase
AU - Toyabe, Shoichi
AU - Watanabe-Nakayama, Takahiro
AU - Okamoto, Tetsuaki
AU - Kudo, Seishi
AU - Muneyuki, Eiro
PY - 2011/11/1
Y1 - 2011/11/1
N2 - 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.
AB - 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.
KW - Electrorotation
KW - Molecular motor
KW - Nonequilibrium physics
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U2 - 10.1073/pnas.1106787108
DO - 10.1073/pnas.1106787108
M3 - Article
C2 - 21997211
AN - SCOPUS:81055145461
SN - 0027-8424
VL - 108
SP - 17951
EP - 17956
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 44
ER -