X-ray analysis of protein dynamics

The structure of human lysozyme has been refined at 1.5 Å resolutions in terms of 1026 protein atoms and 130 water molecules. The current R-factor is 0.187 for the 19000 observed reflections. Although analysis of the structure of the enzyme yields important results, analysis of the vibration data seems even more important. A detailed comparison with the results obtained from and independent refinement of hen lysozyme at 2 Å resolution shows that both molecules have a very similar pattern of atomic displacements which clearly reflects the molecular structure of the protein. The region of high motion includes part of the active site and those residues that undergo conformational changes on substrate binding. These results suggest that analysis of protein dynamics is possible with X-ray diffraction studies