Video Imaging of Protein Molecules in Action by High-speed Atomic Force Microscopy

Abstract

Proteins are dynamic in nature and work at the single-molecule level. Reflecting this fact, single-molecule fluorescence microscopy has been widely exploited to understand how proteins operate. However, what we can observe thereby is the dynamic behaviour of individual fluorescent spots (each being emitted from a fluorophore attached to a selected locus of the molecule), not of the protein molecules themselves. The structure of proteins has been studied by electron microscopy, X-ray crystallography and NMR, but the obtained structures are essentially static. This long-standing problem prevailing throughout biological research has been recently overcome by the development of high-speed atomic force microscopy that enables simultaneous recording of the structure and dynamics of functioning biomolecules with high spatiotemporal resolution.