STRUCTURE OF THE O-SPECIFIC, SIALIC-ACID CONTAINING POLYSACCHARIDE CHAIN AND ITS LINKAGE TO THE CORE REGION IN LIPOPOLYSACCHARIDE FROM HAFNIA-ALVEI STRAIN-2 AS ELUCIDATED BY CHEMICAL METHODS, GAS-LIQUID-CHROMATOGRAPHY MASS-SPECTROMETRY, AND 1H NMR-SPECTROSCOPY

Mild acid hydrolysis of Hafnia alvei strain 2 lipopolysaccharide released no O-specific polysaccharide but instead gave a monomeric octasaccharide repeating unit with N-acetylneuraminic acid as the reducing terminus. In addition, a dimer of the octasaccharide repeating unit, and also a decasaccharide composed of a fragment of the O-specific polysaccharide chain and the core region, were obtained in minute amounts. On the basis of the sugar and methylation analyses, periodate oxidation, and H-1 NMR spectroscopy of the lipopolysaccharide hydrolytic products, the biological repeating unit of the O-specific polysaccharide was shown to be a branched octasaccharide: [GRAPHICS] The linkage between the O-specific polysaccharide chain and core region has also been determined and has yielded strong evidence that N-acetylneuraminic acid is an inherent lipopolysaccharide component. The lipopolysaccharide of H. alvei strain 2 is the first lipopolysaccharide reported to contain 4-substituted neuraminic acid in its O-specific polysaccharide region.