Biological Application of Fast-Scanning Atomic Force Microscopy

Abstract

Recent developments in microscopy technology are remarkable; improvements in temporal and spatial resolution allow us to detect transient states of molecules and biomolecular complexes at the single-molecule level. Atomic force microscopy (AFM) has become an important contributor to physiological and biological cell research. It is a powerful tool in studying the structural organization and dynamics of various biological macromolecules and their assemblies. Current AFM techniques facilitate qualitative and quantitative measurements of diverse cellular processes, ranging from the forces generated by protein–membrane interaction to the mechanism of enzyme reaction at the single-molecule level. In this chapter, we shall focus on the most-recently established technique, fast-scanning AFM. A significant feature of this technique is its capability of directly analyzing conformational changes of biological macromolecules and intermolecular interactions at a single-molecule level on a subsecond time scale under near-physiological conditions. Atomic resolution can be achieved by X-ray crystallography and high resolution electron microscopy (EM). On the other hand, real-time movement of proteins in cells can be monitored under fluorescence microscopy. However, the movement detected under fluorescence microscopy does not uncover the dynamics of the protein shape itself. The applications outlined here, regarding fast-scanning AFM applications, fill the gap between X-ray crystallography/EM and fluorescence microscopy.