High-resolution electron cryomicroscopy of macromolecular assemblies

Electron cryomicroscopy is a high-resolution imaging technique that is part icularly appropriate for the structural determination of large macromolecul ar assemblies, which are difficult to study by X-ray crystallography or NMR spectroscopy. For some biological molecules that fonts two-dimensional cry stals, the application of electron cryomicroscopy and image reconstruction cars help elucidate structures at atomic resolution, its instances where cr ystals cannot be formed, atomic-resolution information call be obtained by combining high-resolution structures of individual components determined by X-ray crystallography or NMR LR with image-derived reconstructions at mode rate resolution. This can provide unique and crucial information on the mec hanisms of these complexes. Finally: image reconstructions can be used to a ugment X-ray studies by providing initial models that facilitate phasing of crystals of large macromolecular machines such as ribosomes aim viruses.