Kriyoelektronmikroskoopia

Kriyoelektronmikroskoopia, often abbreviated as cryo-EM, is a powerful technique used to determine the three-dimensional structure of biological molecules, such as proteins and viruses, at near-atomic resolution. This method involves flash-freezing a sample of the molecules in a thin layer of vitreous ice, which preserves their native structure without the formation of damaging crystals. The frozen sample is then imaged using a transmission electron microscope (TEM).

Unlike traditional X-ray crystallography, which requires molecules to form well-ordered crystals, cryo-EM can be used to study molecules that are difficult or impossible to crystallize. This includes large, complex protein assemblies and membrane proteins. The electron microscope takes many thousands of images of the randomly oriented particles in the ice. Sophisticated computational algorithms are then used to align these images, classify them based on their orientation, and reconstruct a high-resolution 3D map of the molecule.

The resulting density map can then be used to build an atomic model of the molecule. Cryo-EM has revolutionized structural biology, enabling researchers to study a wide range of biological processes and to design new drugs and therapies. Recent advancements in detector technology and computational methods have significantly improved the speed and resolution achievable with cryo-EM, making it an increasingly accessible and indispensable tool for scientists worldwide.