Comparison of structures of dry and wet hen egg-white lysozyme molecule at 1.8 Å resolution

A high resolution structure of hen egg-white lysozyme containing 36 ± I mol H 2O per mol of protein has been obtained using triclinic (P 1) crystals cross-linked with glutaraldehyde. Analysis of dehydration-induced structural changes has revealed displacement in relative position of domains and numerous small displacements in positions of individual atoms with r.m.s. deviation of main atoms 0.60 Å, and that of all atoms 0.97 Å. An increase in the average packing density of atoms in dry lysozyme by 4–6% seems to be the most probable reason for the loss of its activity and mobility.