Hekstra, D.R. et al. Nature 540, 400–405 (2016).

Proteins can be thought of as tiny machines that carry out mechanical functions in the cell. Such mechanics, however, can be very challenging to study. Hekstra et al. describe an approach to following conformational changes in proteins over time in response to applied strong electric field pulses, the idea being that large external electric fields exert forces that stimulate the movement of atoms throughout the protein. The method, electric field–stimulated X-ray crystallography (EF-X), uses timed, fast synchrotron X-ray pulses to capture a series of diffraction snapshots of a protein crystal of interest upon perturbation by electric field pulses. In applying the approach to a human PDZ domain as a model system, the authors observed conformational motions on the submicrosecond timescale that were similar to those observed upon ligand binding.