Time-resolved crystallography.

Time-resolved crystallography has been successfully applied on the time scale from seconds via milliseconds and nanoseconds to picoseconds on a variety of systems. This brief review largely deals with macromolecular systems, on which there has been substantial recent progress. The strategies for design of a successful experiment that eliminates or minimizes potential artefacts have been identified, and the specifically crystallographic components of these strategies have been implemented. The remaining computational challenge is to identify and extract time-independent structures, each corresponding to a distinct reaction intermediate, whose populations vary with time and give rise to the time-dependent X-ray diffraction data. The fourth dimension, time, has been added to the three spatial dimensions of crystallography; it can no longer be regarded as purely a static technique.