Vacuum ultraviolet circular dichroism (VUCD) measurements will be made on dermatan sulfate, keratan sulfate and heparin. The objective will be to delineate the contributions of the various factors which determine VUCD spectra, e.g., carboxylic groups, acetamido groups, protonation, anomeric configuration, linkage type, and intra- and intermolecular hydrogen bonds. By comparing solution spectra, gel spectra (when appropriate) and film spectra, and correlating results with x-ray studies, absolute structural features of these glycosaminoglycans (GAG's) can be determined. The three GAG's included in this project are chosen to determine the effect of replacing the glucuronic acid of hyaluronic acid (previously studied) with the iduronic acid of dermatan; elimanating the uronic acid moiety in a disaccharide repeat as in keratan sulfate; and replacing the glucuronic acid of hyaluronic acid with the iduronic acid of heparin and at the same time changing linkages. VUCD spectra will also be obtained for formyl-L-methionyl-L-leucyl-L-phenylalanine and other chemotactic peptides. These absolute structure studies will allow the sequence dependence of conformation to be correlated with th sequence dependence of chemotactic activity. Hypotheses relating peptide conformation with chemotactic activity can thereby be tested.
