Structure and behaviour of biomolecules from Raman optical activity.

Raman optical activity, which can be measured as a small circularly polarized component in Raman-scattered light from chiral molecules, holds much promise for studying a large range of biomolecules in aqueous solution. Among other things, it provides information about motif and fold, as well as secondary structure, of proteins; the solution structure of carbohydrates; and the structure of the polypeptide and carbohydrate components of intact glycoproteins. In addition, new insights into the structural elements present in unfolded protein sequences, and the structure of the protein and nucleic acid components of intact viruses can be obtained. Ab initio quantum-chemical simulations of observed Raman optical activity spectra provide the complete three-dimensional structure of small biomolecules. Raman optical activity measurements are now routine thanks to the availability of a commercial instrument based on a novel design.