Raman optical activity studies of the influence of water on structure and dynamics of proteins, viruses and nucleic acids

Abstract

A promising technique for studying the effects of solvation on biomol. structure and function is Raman optical activity (ROA), which measures vibrational optical activity by means of a small difference in the intensity of Raman-scattered light from chiral mols. in right- and left-circularly polarized incident light. ROA can be more incisive than conventional vibration spectroscopy in the study of biomols. because only the few vibrational coordinates within a complicated normal mode which sample the skeletal chirality most directly make the largest contributions. Recent results on peptides, proteins and intact viruses suggest that ROA can distinguish a-helix in hydrophobic, amphipathic and fully solvated environments. Fully water-solvated a-helix appears to have an important role, and may be implicated in the conformational diseases. ROA studies of nucleic acids provide evidence that deformations of water mols. couple strongly with some base stretching modes, and reveal a new glass-like transition at .apprx.15-18 Deg which might involve the formation of ordered water structure. [on SciFinder (R)]