CRYOCRYSTALLOGRAPHY OF INFLUENZA-VIRUS HEMAGGLUTININ CRYSTALS

X-ray diffraction data collected at cryogenic temperatures from flash- cooled crystals of influenza virus hemagglutinin show improvements in both resolution and quality relative to data collected at 277 K. These improvements are dramatic for flash-cooled hemagglutinin crystals irr adiated with X-rays from a synchrotron source. At the Cornell High Ene rgy Synchrotron Source hash-cooled hemagglutinin crystals diffracted a t least 0.9 Angstrom farther than hemagglutinin crystals at ambient te mperatures. Radiation damage in the flash-cooled crystals is reduced, making it possible to collect a complete data set from a single hemagg lutinin crystal. However, radiation damage is not eliminated in the fl ash-cooled crystal. As a result the quality of X-ray data can be signi ficantly degraded during long exposure times at a synchrotron source.