Structure of the O-specific polysaccharide from a marine bacterium Echinicola vietnamensis KMM 6221T

Abstract

The O-specific polysaccharide was isolated from the lipopolysaccharide of Echinicola vietnamensis and studied by chemical methods along with 1H and 13C NMR spectroscopy, including 2D 1H, 1H COSY, TOCSY, ROESY, 1H, 13C HSQC, HMBC, and H2BC experiments. It was found that the polysaccharide is built up of branched tetrasaccharide repeating units, containing 2-acetamido-2-deoxy-d-glucuronic acid (GlcNAcA), 2-acetamido-2-deoxy-d-galactose (GalNAc), and d-glucuronic acid (GlcA) with a terminal residue of 3,6-dideoxy-l-xylo-hexose (colitose, Col) and has the following structure.