cryo-EM

In cryo-EM, researchers rapidly freeze a cell, virus, chemical complex, or other structure to prevent the formation of ice crystals. This maintains the original status of the sample. An electron microscope is used by scientists to blast the frozen sample with an electron beam. This creates a projection of the sample in two dimensions on a digital detector. Scientists build a three-dimensional model of a sample's structure by generating hundreds of projections of the sample from a variety of angles and then averaging these projections. Recent breakthroughs in cryo-EM offer images of proteins and other biological structures, including bigger structures like RNA-protein complexes, in exquisite detail.