11] Single-molecule imaging of rotation of F1-ATPase

Abstract

Publisher Summary A single molecule of F 1 -ATPase has been shown to be a rotary motor, driven by ATP hydrolysis, in which the central γ subunit rotates against a surrounding cylinder made of alternately arranged three α and three β subunits. At present, F1-ATPase is one of the best characterized molecular motors or nucleotide-driven molecular machines. It is possible to learn a lot from this rotary machine about the molecular mechanism of chemomechanical energy transduction. Single-molecule imaging with a large or small probe is a versatile tool for the investigation of the mechanisms of protein machines, revealing their conformational changes in real time. Probes that are large compared to protein molecules are easily observed by conventional microscopy. The interpretation of the images is often straightforward, and intense signals from a large probe allow precise analysis. In contrast, probes smaller than protein molecules—such as single fluorophores—are much less perturbing and enable observation under no load.