Experimental evidence for the benefits of higher X-ray energies for macromolecular crystallography

Abstract

X-ray induced radiation damage is a limiting factor for the macromolecular crystallographer and data must often be merged from many crystals to yield complete datasets for structure solution of challenging samples. Increasing the X-ray energy beyond the typical 10-15 keV range promises to provide an extension of crystal lifetime via an increase in diffraction efficiency. To date however hardware limitations have negated any possible gains. Through the first use of a Cadmium Telluride Eiger2 detector and a beamline optimised for high energy data collection, we show that at higher energies fewer crystals will be required to obtain complete data, as the diffracted intensity per unit dose increases by a factor of more than 3 between 12.4 and 25 keV. Additionally, those higher energy data provide more information, evidenced by an increase in high-resolution limit of up to 0.3 [A], pointing to a high energy future for synchrotron-based macromolecular crystallography.