Classical Light Scattering for the Determination of Absolute Molecular Weights and Gross Conformation of Biological Macromolecules

Classical light scattering, like sedimentation equilibrium in the analytical ultracentrifuge, can provide a powerful absolute method for the determination of molecular weights of macromolecules. By “classical” light scattering (as opposed to “dynamic” light scattering [cf. Chapter 8]) we mean the measurement of the total or time-integrated intensity scattered by a macromolecular solution compared with the incident intensity for a range of concentrations and/or angles; this information can be used to deduce the mol wt, M, gross conformation (from measurement of a parameter commonly referred to as the “radius of gyration,” RG), and thermodynamic nonideality parameters (particularly the thermodynamic second virial coefficient, B, which can also yield potentially useful information on molecular conformation). Classical light scattering is often referred to in the literature as “total intensity light scattering” (“TILS”), “static light scattering,” “integrated light scattering, “ ”differential light scattering,“ ”traditional light scattering,“ or simply “light scattering.”