Influence of Glycerol on the Structure and Thermal Stability of Lysozyme: A Dynamic Light Scattering and Circular Dichroism Study

Photon correlation spectroscopy and circular dichroism have been used to study the role of hydration in the
structure and thermostability of the model protein lysozyme in water-glycerol mixtures. Two cases have
been considered: water-rich and glycerol-rich regimes of concentrations. We follow the thermal denaturation
both by optical spectral changes and hydrodynamic radius variations. This methodology allows us to emphasize
the relevant role played by hydrophobic interactions during the process in aqueous solutions and, in glycerol,
to distinguish the non-cooperative melting of secondary structure, supporting the view of a protein transition
to a molten globule-like state.