New technique shocks proteins into action

Abstract

For a protein to carry out its job—whether it be replicating DNA, metabolizing fuel, transporting biomolecules, or sending cell signals—its amino acids have to move in certain ways. The patterns of these internal motions aren’t always well understood because the tools available to study them are limited. A new technique, electric field-stimulated X-ray crystallography (EF-X), combines electric pulses with time-resolved X-ray crystallography to provide more comprehensive views of the ways proteins work. Electrical charges and dipoles are present in all proteins, and external electric fields exert forces on them, causing atoms to move. In EF-X, developed by a research team led by Rama Ranganathan of the University of Texas Southwestern Medical Center, electric field pulses activate conformational changes of amino acids throughout protein molecules in crystals, and fast X-ray pulses then visualize those motions (Nature 2016, DOI: 10.1038/nature20571). Ranganathan and coworkers used EF-X to visualize motions ...