Thermal Denaturation of Interfacial Protein Layers

Abstract

We report for the first time the structural measurements at nanometre resolution of the denaturation of β-lactoglobulin and lysozyme at an air–water interface using the technique of neutron reflectivity. The incipient denaturation shown previously[1] for myogloblin is also studied for these molecules at room temperature, and denaturation is provoked by increasing the temperature of the solutions progressively to 75°C. The change in the adsorbed protein layer thickness, its scattering length density and density distribution perpendicular to the surface as a function of increased temperature are reported and the data analysed in terms of a two-state model for the denaturation process. These measurements are relevant to an understanding of the way in which proteins at interfaces act as templates, for example, in biomineralization.