Mechanically driven ATP synthesis by F1-ATPase.
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 gamma-subunit rotates against the surrounding alpha3beta3 subunits, hydrolysing ATP in three separate catalytic sites on the beta-subunits. It is widely believed that reverse rotation of the gamma-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 gamma-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.
Itoh
Hiroyasu
H
Tsukuba Research Laboratory, Hamamatsu Photonics KK, Joko, Hamamatsu 431-3103, Japan. hiritoh@hpk.trc-net.co.jp
Takahashi
Akira
A
Adachi
Kengo
K
Noji
Hiroyuki
H
Yasuda
Ryohei
R
Yoshida
Masasuke
M
Kinosita
Kazuhiko
K
D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000138:chemical synthesis / Q000378:metabolism*; D001407:Bacillus / Q000201:enzymology; D002384:Catalysis; D005898:Glass; D008280:Magnetics; D008832:Microchemistry; D008863:Microspheres; D020409:Molecular Motor Proteins / Q000378:metabolism; D006180:Proton-Translocating ATPases / Q000378:metabolism*; D012399:Rotation; D019415:Torque
D020409:Molecular Motor Proteins; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D006180:Proton-Translocating ATPases