Proteins serve as the primary molecular machinery of life, maintaining the functional order of our cells. As their structure informs their function, accurate determination of structural information is the basis of biological insights for any number of physiological, pharmaceutical, and biomaterial advances.
Cryo-electron microscopy (cryo-EM) is an established method for the determination of 3D structural information for a wide range of biomolecules, including proteins and protein complexes.
Until recently, proteins had to be crystallized to reconstruct and visualize them with X-ray crystallography. This information came with several stipulations; crystallization is time consuming and can typically only work on single purified protein (monomers or dimers); additionally, some proteins do not crystallize. Finally, the structure has to be determined outside of the cellular environment, removing vital contextual information.
Cryo-EM, which is comprised of several applications like single particle analysis (SPA), cryo-electron tomography (cryoET), and micro electron diffraction (MicroED), has revolutionized the study of proteins, their complexes, and their dynamics.
- Single particle analysis (SPA) – Images and analyzes small (<250kDa) and intermediate sized proteins (>250kDa) as well as large protein complexes with high throughput and high resolution.
- Cryo tomography (cryoET) – Ideal for the analysis of cellular components and fractions at intermediate resolutions. It provides cellular context to the macromolecular structures determined with single particle analysis.
- Micro electron diffraction (MicroED) – Suited for structural determination of small sub-750-nm protein crystals, a unique class of crystals that cannot be analyzed by traditional X-ray crystallography.
