Learn More
Myosin V is a two-headed, actin-based molecular motor implicated in organelle transport. Previously, a single myosin V molecule has been shown to move processively along an actin filament in discrete approximately 36 nm steps. However, 36 nm is the helical repeat length of actin, and the geometry of the previous experiments may have forced the heads to bind(More)
A single molecule of F1-ATPase is by itself a rotary motor in which a central gamma-subunit rotates against a surrounding cylinder made of alpha3beta3-subunits. Driven by the three betas that sequentially hydrolyse ATP, the motor rotates in discrete 120 degree steps, as demonstrated in video images of the movement of an actin filament bound, as a marker, to(More)
Myosin VI is a two-headed molecular motor that moves along an actin filament in the direction opposite to most other myosins. Previously, a single myosin VI molecule has been shown to proceed with steps that are large compared to its neck size: either it walks by somehow extending its neck or one head slides along actin for a long distance before the other(More)
F(1)-ATPase is a rotary molecular motor that proceeds in 120 degrees steps, each driven by ATP hydrolysis. How the chemical reactions that occur in three catalytic sites are coupled to mechanical rotation is the central question. Here, we show by high-speed imaging of rotation in single molecules of F(1) that phosphate release drives the last 40 degrees of(More)
F1-ATPase is a rotary motor made of a single protein molecule. Its rotation is driven by free energy obtained by ATP hydrolysis. In vivo, another motor, Fo, presumably rotates the F1 motor in the reverse direction, reversing also the chemical reaction in F1 to let it synthesize ATP. Here we attempt to answer two related questions, How is free energy(More)
Orientation dependence of single-fluorophore intensity was exploited in order to videotape conformational changes in a protein machine in real time. The fluorophore Cy3 attached to the central subunit of F(1)-ATPase revealed that the subunit rotates in the molecule in discrete 120 degrees steps and that each step is driven by the hydrolysis of one ATP(More)
F1-adenosine triphosphatase (ATPase) is an ATP-driven rotary molecular motor in which the central gamma subunit rotates inside a cylinder made of three alpha and three beta subunits alternately arranged. The rotor shaft, an antiparallel alpha-helical coiled coil of the amino and carboxyl termini of the gamma subunit, deeply penetrates the central cavity of(More)
Vacuole-type ATPases (V(o)V₁) and F(o)F₁ ATP synthases couple ATP hydrolysis/synthesis in the soluble V(1) or F₁ portion with proton (or Na(+)) flow in the membrane-embedded V(o) or F(o) portion through rotation of one common shaft. Here we show at submillisecond resolutions the ATP-driven rotation of isolated V₁ and the whole V(o)V₁ from Thermus(More)
F(1)-ATPase is a rotary molecular motor in which the central gamma subunit rotates inside a cylinder made of alpha(3)beta(3) subunits. To clarify how ATP hydrolysis in three catalytic sites cooperate to drive rotation, we measured the site occupancy, the number of catalytic sites occupied by a nucleotide, while assessing the hydrolysis activity under(More)
F(1)-ATPase is an ATP-driven rotary molecular motor in which the central gamma-subunit rotates inside the cylinder made of alpha(3)beta(3) subunits. The amino and carboxy termini of the gamma-subunit form the axle, an alpha-helical coiled coil that deeply penetrates the stator cylinder. We previously truncated the axle step by step, starting with the longer(More)