X-ray crystallographic investigation of radiation damage to alpha-chymotrypsin

This thesis describes the application of an efficient area detector system and a rotation camera to the measurement of x-ray diffraction patterns from a single crystal of alpha-chymotrypsin (αCT), with low total dose of x-irradiation for each of three complete rotations. This permits testing models of the radiation damage process used for correcting diffraction data. The model of Blake and Phillips as modified by Hendrickson was found to be inconsistent with the data obtained. A more relaxed model was also found to be inadequate. The evolution of the diffraction pattern as the dose accumulates indicates that very similar shifts in electron density must be occurring in large numbers of the αCT molecules, shifts not describable simply in terms of random disorder