Nature 427, 465 - 468 (29 January 2004); doi:10.1038/nature02212

Mechanically driven ATP synthesis by F₁-ATPase

HIROYASU ITOH^1,2, AKIRA TAKAHASHI³, KENGO ADACHI⁴, HIROYUKI NOJI⁵, RYOHEI YASUDA⁶, MASASUKE YOSHIDA⁷ & KAZUHIKO KINOSITA JR⁴

¹ Tsukuba Research Laboratory, Hamamatsu Photonics KK, Joko, Hamamatsu 431-3103, Japan
² CREST "Creation and application of soft nano-machine, the hyperfunctional molecular machine" Team 13*, Tokodai, Tsukuba 300-2635, Japan
³ System Division, Hamamatsu Photonics KK, Joko, Hamamatsu 431-3103, Japan
⁴ Center for Integrative Bioscience, Okazaki National Research Institutes, Okazaki 444-8585, Japan
⁵ Institute of Industrial Science, University of Tokyo, Tokyo 153-8505, Japan
⁶ Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724 USA
⁷ ERATO "ATP System", 5800-3 Nagatsuta, Yokohama 226-0026, Japan

Correspondence and requests for materials should be addressed to H.I. (hiritoh@hpk.trc-net.co.jp).

ATP, the main biological energy currency, is synthesized from ADP and inorganic phosphate by ATP synthase in an energy-requiring reaction. The F₁ portion of ATP synthase, also known as F₁-ATPase, functions as a rotary molecular motor: in vitro its -subunit rotates against the surrounding ₃₃ subunits, hydrolysing ATP in three separate catalytic sites on the -subunits. It is widely believed that reverse rotation of the -subunit, driven by proton flow through the associated F_o portion of ATP synthase, leads to ATP synthesis in biological systems. Here we present direct evidence for the chemical synthesis of ATP driven by mechanical energy. We attached a magnetic bead to the -subunit of isolated F₁ on a glass surface, and rotated the bead using electrical magnets. Rotation in the appropriate direction resulted in the appearance of ATP in the medium as detected by the luciferase–luciferin reaction. This shows that a vectorial force (torque) working at one particular point on a protein machine can influence a chemical reaction occurring in physically remote catalytic sites, driving the reaction far from equilibrium.