Protein function in the crystal.

Protein crystals contain wide solvent-filled channels that allow for traffic of metabolites and intramolecular motility. Ligand binding, catalysis and allosteric regulation occur in the crystalline environment but intermolecular interactions may hinder function-associated transitions and alter activity with respect to solution. Lattice constraints have, however, provided the opportunity to isolate and characterize conformational states that are poorly populated in solution. New methods are being developed to initiate reactions rapidly and synchronously throughout the crystal and to monitor their time course. A model consistent with kinetics in the crystal is necessary to interpret the results of time-resolved macromolecular crystallography.