A preliminary neutron diffraction study of γ-­chymotrypsin

The crystal preparation and preliminary neutron diffraction analysis of γ-­chymotrypsin are presented. Large hydrogenated crystals of γ-chymotrypsin were exchanged into deuterated buffer via vapor diffusion in a capillary and neutron Laue diffraction data were collected from the resulting crystal to 2.0 A resolution on the LADI-III diffractometer at the Institut Laue–Langevin (ILL) at room temperature. The neutron structure of a well studied protein such as γ-­chymotrypsin, which is also amenable to ultrahigh-resolution X-ray crystallo­graphy, represents the first step in developing a model system for the study of H atoms in protein crystals.