Complementary use of high-resolution and high-precision cryo-ED and EM

Abstract

Cryo-electron microscopy (cryo-EM) is widely used to determine high-resolution structures from images of protein molecules embedded in thin ice and from electron diffraction patterns of small and thin crystals. These two techniques of imaging and diffraction offer complementary structure analysis of various-sized molecules: The former single particle analysis is applied mainly to larger-sized molecules that yield good image contrast in vitreous ice; Electron 3D crystallography (3D ED / MicroED) is applicable to undersized crystals of smaller molecules, which are hard to solve by single particle analysis and do not grow to a suitable size for X-ray diffraction even with a high-intensity synchrotron radiation beam. The former application has value in structural biology, while the importance of the latter is becoming recognized in synthetic chemistry, material sciences and related areas.