Vacuum-ultraviolet circular dichroism analysis of glycosaminoglycans by synchrotron-radiation spectroscopy

Abstract

Glycosaminoglycans (GAGs) are important polysaccharides with various biological functions, but their structures in solution are affected in a complex manner by their component residues. We successfully measured the vacuum-ultraviolet circular dichroism (VUVCD) spectra of six GAGs (chondroitin, chondroitin sulfates, hyaluronic acid, and heparin) and their component sugars (N-acetylaminosugars and uronic acid) from 240 to 160nm by a synchrotron-radiation VUVCD spectrophotometer in aqueous solutions at 25 °C. These comprehensive VUVCD spectra revealed the characteristic contribution of the constituent functional groups (sulfate, carboxyl, hydroxyl, hydroxymethyl, acetamido, etc.) and intersaccharide linkages to the higher energy transition of oxygen lone-pair electrons, giving basic information for understanding the detailed structures of GAGs in solution and for their theoretical assignment.