Three-dimensional electron cryo-microscopy as a powerful structural tool in molecular medicine.
Electron cryo-microscopy has established itself as a valuable method for the structure determination of protein molecules, protein complexes, and cell organelles. This contribution presents an introduction to the various aspects of three-dimensional electron cryomicroscopy. This includes the need for sample preservation in the microscope vacuum, strategies for minimizing radiation damage, methods of improving the poor signal-to-noise ratio in electron micrographs of unstained specimens, and the various methods of three-dimensional image reconstruction from projections. The various specimen types (e.g., flat and tubular two-dimensional crystals, protein filaments, individual protein molecules, and large complexes) require different means of three-dimensional reconstruction, and we review the five major reconstruction techniques (electron crystallography, helical reconstruction, icosahedral reconstruction, single-particle reconstruction, and electron tomography), with an emphasis on electron crystallography. Several medically relevant three-dimensional protein structures are chosen to illustrate the potential of electron cryo-microscopy and image reconstruction techniques. Among the structural methods, electron cryo-microscopy is the only tool for studying objects that range in size from small proteins over macromolecular complexes to cell organelles or even cells.
Skirball Institute of Biomolecular Medicine, New York University Medical Center, NY 10016, USA. auer@saturn.med.nyu.edu
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M
Auer
D020285:Cryoelectron Microscopy / Q000295:instrumentation / Q000379:methods*; D018360:Crystallography, X-Ray; D006801:Humans; D021621:Imaging, Three-Dimensional; D009682:Magnetic Resonance Spectroscopy; D008854:Microscopy, Electron; D015394:Molecular Structure; D011506:Proteins / Q000737:chemistry / Q000648:ultrastructure; D011978:Receptors, Nicotinic / Q000737:chemistry / Q000378:metabolism; D012270:Ribosomes / Q000737:chemistry / Q000378:metabolism; D014780:Viruses / Q000737:chemistry / Q000648:ultrastructure
D011506:Proteins; D011978:Receptors, Nicotinic