[Structure of the repeating link of the acid polysaccharide of Alteromonas haloplanktis KMM 156].

An acidic capsular and an O-specific polysaccharide were isolated from the marine microorganism Alteromonas haloplanktis KMM 156. Both polysaccharides have the identical structure and are built up of tetrasaccharide repeating units, containing two residues of L-rhamnose as well as a 2-acetamido-2-deoxy-D-glucose and a 3-O-[(R)-1-carboxyethyl]-D-glucose (Glc3Lac) residue. On the basis of methylation studies, 1H- and 13C-NMR-spectroscopy including nuclear Overhauser effect and two-dimensional heteronuclear 13C/1H correlation spectroscopy, the following structure was suggested for the polysaccharide repeating unit: [formula: see text]