Structures of Complex Polysaccharides

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Research is proposed in the determination of the covalent structure of biochemically interesting complex carbohydrates by physical methods including NMR spectroscopy, high performance liquid chromatography and mass spectrometry. Several specific experiments are proposed in the structure of oligosaccharides from mucin glycoproteins and also in complex bacterial polysaccharides. The prospect of using NMR spectroscopy of intact glycoproteins for exploring and screening carbohydrate structure in mucins will be evaluated. 1H NMR and heteronuclear 1H detected 13C NMR spectroscopy will be used. The complete covalent structure of the capsular polysaccharide of a pathogenic strain of Vibrio vulnificus will be determined. The complete 1H and 13C NMR spectra of the Re-LPS (lipid A) from E. coli will be assigned and the anomeric configuration of the ketodeoxy octanoic acid (KDO) residues will be determined. Prospects for use of heteronuclear NMR spectroscopy for structure determination of lipopolysaccharides and exploration of the conformation will be evaluated. The circular dichroism method for determination of the absolute configuration of the sugar residues of complex carbohydrates will be extended to new types of monosaccharide residues and chromophoric polysaccharides. The use of 13C-enriched bacterial polysaccharides for heteronuclear NMR spectroscopy, especially 3-dimensional NMR methods will be explored.