A New Perspective on Protein Structure and Dynamics from Raman Optical Activity

The vlue of vibrational spectroscopy in the study of biopolymers has been greatly enhanced by adding the new dimension of optical activity [1]. The Raman optical activity (ROA) approach, which measures a small difference in the intensity of Raman scattering in right and left circularly polarized incident light, has been transformed by recent technical advances into a powerful new biochemical spectroscopy [2]. Since protein ROA spectra contains bands from loops and turns in addition to secondary structure, they contain information about the tertiary backbone fold and hence the three-dimensional solution structure. This, plus a special sensitivity to conformational mobility and the short timescale of the Raman scattering process, makes ROA ideal for studying dynamic aspects of structure in both non-native [3, 4] and native [5] states.