STRUCTURE OF THE REPEATING UNIT OF THE ACIDIC POLYSACCHARIDE FROM ALTEROMONAS-HALOPLANKTIS KMM 156

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