Structure of the O-specific polysaccharide from the lipopolysaccharide of Aeromonas hydrophila strain K691 containing 4-acetamido-4,6-dideoxy-d-glucose.

The O-specific polysaccharide (OPS) was isolated from the lipopolysaccharide of Aeromonas hydrophila strain K691 and studied by chemical methods and H and C NMR spectroscopy, including 2D H,H COSY, TOCSY, NOESY, H-detected heteronuclear H,C HSQC, and HMBC experiments. It was found that the O-specific polysaccharide was built up of pentasaccharide repeating units composed of β-GlcpNAc, 2-O-acetylated α-Rhap, and β-Quip4NAc residues. The following structure of the OPS was established: →3)-α-l-Rha2OAc-(1→3)-β-d-GlcNAc-(1→3)-α-l-Rha2OAc-(1→3)-β-d-GlcNAc-(1→2)-β-d-Qui4NAc-(1→.