Beyond blob-ology

摘要

Structural biology aims to obtain high-resolution snapshots of the macro-molecules that make up living cells. Most have come from x-ray crystallography or nuclear magnetic resonance (NMR) spectroscopy. However, x-ray crystallography is limited by the ability to grow well-ordered three-dimensional (3D) crystals, whereas NMR spectroscopy requires highly concentrated samples with nonoverlapping spectral peaks. Many macromolecular assemblies are too large, scarce, or unstable for analysis by these techniques. Single-particle electron microscopy (EM) offers an alternative, allowing high-resolution structures to be determined from small quantities of noncrystalline material.