Structure analyses of biomolecules using a synchrotron radiation circular dichroism spectrophotometer

Abstract

The vacuum-ultraviolet circular dichroism (VUVCD) spectra of various saccharides and proteins were measured in aqueous solution down to 160 nm, using a VUVCD spectrophotometer at the Hiroshima Synchrotron Radiation Center (HSRC). Most mono- and disaccharides exhibit characteristic peaks at around 170 nm that are sensitive to the anomeric and axial/equatorial configurations of hydroxyl groups, trans– gauche conformations of hydroxymethyl group, and the type of glycosidic linkage. The VUVCD spectra of proteins below 190 nm exhibit characteristic bands corresponding to the different secondary structures. Predicting the content and number of α-helix and β-strand segments is greatly improved, when lower wavelength CD spectra are available. These results demonstrate that synchrotron radiation VUVCD spectroscopy is useful for structure analyses of biomolecules based on the higher energy transitions of chromophores including hydroxyl and acetal groups.