The tools of structural biology have become more powerful during the last 60 years. The first protein structure, that of sperm whale myoglobin, was solved in 1960 using X-ray crystallography, a method that has grown to produce over 10,000 structures per year, all of them being deposited in the Protein Data Bank (PDB). In recent years, electron cryomicroscopy (cryoEM) of single particles plunge-frozen in a thin film of amorphous ice, has developed rapidly in power and resolution, so that over 2,000 PDB depositions are now made each year for structures solved by cryoEM. Many of these cryoEM structures represent unstable or flexible assemblies whose structure cannot be determined by any other method, and almost all of them involve images collected on 300 keV state-of-the-art transmission electron cryo-microscopes.
1. Kuhlbrandt, W. (2014) The resolution revolution. Science 343, 1443-144.
2. Vinothkumar, K.R. & Henderson, R. (2016) Single particle electron cryomicroscopy: trends, issues and future perspective. Quart. Rev. Biophysics 49, e13, 1-25.