Cryo-Electron Tomography allows direct 3D visualization of a specimen.

In recent years, cryo-electron microscopy (cryo-EM) has become a standard approach in structural biology, it is limited to looking at single layers particles in ice. As specimens become more complex or crowded, particle densities begin to overlap, confounding the identification of components and preventing further analysis. This makes complex specimens such as membrane-associated complexes or cellular sections unammenable to standard cryo-EM approaches.

Cryo-electron tomography (cryo-ET) is a special subset of cryo-EM, where rather than taking a single image, a field of view is imaged multiple times while tilting the specimen. By taking a set of images at different views, a three-dimensional representation of the specimen can be reconstructed, bypassing the overlap problem, and allowing for the study of molecules in complex environments. While tomograms are typically low resolution, futher processing of cryo-ET data, such as by subtomogram averaging, can yield high-resolution molecular structures.

In order to understand viral life cycles, the bulk of our work will be studying viral components in complex, near-native environments. This includes molecular assemblies within intact viruses or virus-like particles, or viral machinery within host cells. It is only within these environments where we obtain structural information with proper biological context. As such, to obtain the best biological results, part of our group’s focus is to optimize and develop cryo-ET methods, including sample preparation, data collection, and computational approaches.