Mild alkaline degradation of the lipopolysaccharide of Escherichia coli O80 afforded a polysaccharide, which was studied by sugar analysis, selective cleavage of glycosidic linkages, and (1)H and (13)C NMR spectroscopy. Solvolysis of the polysaccharide with CF3CO2H cleaved the linkages of α-Fuc and β-linked GlcNAc and GalNAc residues to give two disaccharides. The following structure of the hexasaccharide repeating unit of the O-polysaccharide was established: The polysaccharide repeat also contains a minor O-acetyl group but its position was not determined. The O-antigen gene cluster of E. coli O80 between the conserved galF and gnd genes was analyzed and found to be consistent with the O-polysaccharide structure established.
O-antigen, Escherichia coli, O-polysaccharide, bacterial polysaccharide structure, O-antigen gene cluster
NCBI PubMed ID: 27454490Publication DOI: 10.1016/j.carres.2016.07.011Journal NLM ID: 0043535Publisher: Elsevier
Correspondence: yknirel@gmail.com
Institutions: N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, China
Methods: 13C NMR, 1H NMR, NMR-2D, sugar analysis, acid hydrolysis, GLC, Smith degradation, NMR-1D, GPC, mild acid degradation, function analysis of gene clusters, CF3CO2H solvolysis