Imaging of Movement and Chemical Reactions of Single Biomolecules

Abstract

A new technique for imaging single fluorescent dye molecules in aqueous solution has been developed by refining epifluorescence and total internal reflection fluorescence microscopies. This approach enabled us to directly image the processive movement of individual fluorescently labeled kinesin molecules along a microtubules. This method was also used to visualize individual ATPase reactions of single myosin molecules. Single molecule imaging using green fluorescent protein as a fluorescent tag allowed us to assay functions of single protein molecules expressed in vitro. This method can be applied to examining other enzymatic reactions, interaction of polymerases and helicases with DNA, and a variety of protein-protein or protein-ligand associations at a single molecular level.