Structural characterization of proteins and viruses using Raman optical activity

Abstract

The sensitivity to chirality of Raman optical activity (ROA), which we measure as a small difference in vibrational Raman scattering from chiral molecules in right- and left-circularly polarized incident light, makes it a powerful probe of the structure and behaviour of biomolecules in aqueous solution. Protein ROA spectra provide information on the secondary and tertiary structure of the polypeptide backbone and effects of the local environment, including hydration and the side chain conformations of particular residues. The large number of structure-sensitive bands in protein ROA spectra is especially favourable for fold determination using pattern recognition techniques. Intact viruses may also be studied and their ROA spectra provide information not only on the folds of the coat proteins but also about the conformation of the encapsidated nucleic acid. In this article we present the ROA spectra of several proteins and viruses in order to illustrate some of the applications of ROA spectroscopy in biomolecular research.