Structural determination of the O-antigenic polysaccharide of enteropathogenicEscherichia coliO103:H2

Abstract

The structure of the antigenic O-polysaccharide isolated from the lipopolysaccharide produced by enterohemorrhagic Escherichia coli O103:H2 was determined and shown to be composed of d-glucose (1 part), 2-acetamido-2-deoxy-d-glucose (2 parts), 2-acetamido-2-deoxy-d-galactose (1 part), and 3-deoxy-3-(R)-3-hydroxybutyramido-d-fucose (1 part). From the results of methylation analysis, Smith-type periodate oxidation degradation studies, and the use of one- and two-dimensional1H and13C NMR spectroscopy, the O-polysaccharide antigen was found to be an unbranched polymer of a repeating pentasaccharide unit having the following structure: →2)-β-d-Glcp-(1→2)-β-d-Fucp3NBu-(1→6)-α-d-GlcpNAc-(1→4)-α-d-GalpNAc-(1→3)-β-d-GlcpNAc-(1→, where Bu is (R)-3-hydroxybutyramido.