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

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 160 nm by a synchrotron-radiation VUVCD spectrophotometer in aqueous solutions at 25 degrees 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.