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(1-3). The F-1 portion of ATP synthase, also known as F-1-ATPase, functions as a rotary molecular motor: in vitro its gamma-subunit rotates(4) against the surrounding alpha(3)beta(3) subunits(5), 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(1-3,6,7). 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 F-1 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.