STRUCTURAL STUDIES OF THE O-POLYSACCHARIDE FROM THE LIPOPOLYSACCHARIDE OF MORAXELLA (BRANHAMELLA) CATARRHALIS SEROTYPE-A (STRAIN ATCC-25238)

The polysaccharide of the Moraxella (Branhamella) catarrhalis serotype A lipoporysaccharide was prepared by mild acid hydrolysis followed by gel permeation chromatography. The structure was established by methylation analysis, mass spectrometry, and NMR spectroscopy. It is concluded that the O-antigenic polysaccharide has the following structure. [GRAPHICS] Methylation analysis of the intact lipopolysaccharide showed that the lipid A portion consisted of 6-substituted glucosamine residues. Methylation followed by methanolysis showed that two Kdo residues were present, one terminal and one 4,5-substituted residue. A terminal Kdo thus substitutes the branch-point Kdo in the 4-position.