Cryo-electron microscopy may be the new kid on the structural biology block, but it is a technique on the rise. Although X-ray crystallography remains the dominant technique for solving structures because of its fine atomic resolution, not every protein (especially large complexes) will crystallize, and those that can are sometimes not sufficiently abundant to work with. That's where cryoEM comes in.
CryoEM is a form of electron microscopy that produces sub-nanometer-resolution 3D structures from 2D images of flash-frozen samples. It takes four different forms, of which single particle reconstruction and cryo-electron tomography are the most common variants. In the former, thousands of individual complexes are imaged and computationally averaged to produce a 3D rendering; in the latter, a sample is imaged from a variety of tilt angles to reproduce a 3D volumetric structure, without averaging.
Typically, a sample is spotted onto a copper grid covered with a thin film of ...
