Small is beautiful: Viewing hydrogen atoms with neutron protein crystallography
(Phys.org)—Creating 3D visualizations of hydrogen atoms in proteins is especially challenging, often requiring their locations to be inferred from those of nearby carbon, nitrogen, oxygen or sulfur atoms stored in protein structure databases. These locations are based on atomic positions in databases of previously solved structures, general chemical knowledge, quantum mechanical calculations, or potential hydrogen bonding interactions. While X-ray crystallography can pinpoint hydrogen atom locations at ultrahigh resolution, in practice only a few such positions are experimentally determined. Recently, however, scientists at the University of Toledo, Los Alamos National Laboratory and Oak Ridge National Laboratory used neutron crystallography – a technique that even at lower resolutions can locate individual hydrogen atoms by leveraging scattering properties of the hydrogen isotope deuterium.