The molecule is a polysaccharide derivative comprised of a [2)-alpha-L-Rhap(III)-(1->2)-alpha-L-Rhap(II)-(1->3)-beta-D-GalpA-(1->3)-beta-D-GalpNAc-(1->] tetrasaccharide repeat modified by the addition of an acetyl group to either O-3 or O-4 of many of the Rha(III) residues (60% to O-3; 30% to O-4). The structure provided is representative of that in Shigella flexneri serotype 6 and shows the most common repeating unit. It has a role as an antigen.
(2S,3R,4S,5R,6R)-6-[(2R,3R,4R,5R,6R)-3-acetamido-2,5-dihydroxy-6-(hydroxymethyl)oxan-4-yl]oxy-5-acetyloxy-3-[(2R,3R,4R,5R,6S)-3-[(2S,3R,4R,5S,6S)-4-acetyloxy-3,5-dihydroxy-6-methyloxan-2-yl]oxy-4,5-dihydroxy-6-methyloxan-2-yl]oxy-4-hydroxyoxane-2-carboxylic acid