Cryoelektronimikroskoopia

Cryoelektronimikroskoopia, often abbreviated as cryo-EM, is a powerful microscopy technique used to determine the three-dimensional structure of biological macromolecules. It involves flash-freezing a sample in a thin layer of vitreous ice, which preserves the native state of the molecules without forming damaging ice crystals. The frozen sample is then imaged using a transmission electron microscope (TEM).

Thousands of images of individual molecules, or small complexes, are collected from different angles. Sophisticated computational algorithms are then used to align these 2D projections and reconstruct them into a high-resolution 3D density map. From this density map, an atomic model of the molecule can be built, revealing its structure and how it functions.

Cryo-EM has revolutionized structural biology, particularly for large and dynamic protein complexes that are difficult to crystallize for X-ray crystallography. It allows researchers to study molecules in near-native conditions and provides insights into their mechanisms of action, interactions with other molecules, and conformational changes. The resolution achievable with modern cryo-EM instruments is often comparable to that obtained by X-ray crystallography, making it a crucial tool for understanding biological processes at the molecular level. Its applications span diverse fields, including virology, neuroscience, and drug discovery.