Sit on this and rotate!

The Kinosita Lab has published another paper in Science on F1-ATPase. F-ATPases are used by mitochondria to transform proton gradients energy into ATP via rotation, like a miniature water wheel. But, Kinosita showed in 1997 that, supplied with ATP, the reaction was reversible, and F₁-F_o ATPase could act as a tiny rotary motor. By attaching fluorescently labeled actin filaments to the stalk, they were able to directly visualize rotation of the motor in vitro.


Further work showed that the motor takes discreet 120 degree steps, with 40 and 80 degree substeps. Their most recent paper studied truncated versions of the ATPasae, in which the "axel" that extends down into the "housing" was truncated. They showed that, even without the axel, the "wheel" will still rotate in the correct direction, demonstrating that the axel is not necessary for torque generation (though it makes it much more efficient.)