Electron Microscopy and Single Particle Analysis for Solving Three-Dimensional Structures of Macromolecules

Abstract Structural biology is a well-known branch of biology where insights into the three-dimensional structures of macromolecules are of major concern. Conventionally, X-ray diffraction/crystallography and nuclear magnetic resonance techniques were the primary choices to a structural biologist until the recent addition of a novel technique—the single particle analysis (SPA) in combination with electron microscope (EM). This chapter is aimed at giving an outline of SPA and EM. A brief introduction to the theory and sample preparation techniques of electron microscope will be given followed by discussing the basic principles of SPA. A comparison of the three principal tools in structural biology will also be presented highlighting the strengths and weaknesses of each technique. A brief account of the instrumentation of the transmission electron microscope was presented with a note on various sample preparation methods. After giving a brief introduction to the principles of the SPA, this chapter also discusses some of the recent groundbreaking results published in the recent past. This chapter also attempts to list and discuss the software available for carrying out SPA. Also presented will be other possible but less explored tools where EM had demonstrated its strengths. These include electron two-dimensional crystals and cryo-negative staining.