The molecule is a polysaccharide derivative comprised of a [2)-alpha-L-Rhap(III)-(1->2)-alpha-L-Rhap(II)-(1->3)-alpha-L-Rhap(I)-(1->3)-beta-D-GlcpNAc-(1->] tetrasaccharide repeat modified by the (1->4) linkage of an alpha-D-glucosyl group to the GlcNAc residue and by addition of acetyl groups to O-2 of 80% of the Rha(I) residues and to either O-3 or O-4 of many of the Rha(III) residues (70% to O-3; 15% to O-4). The structure provided is representative of that in Shigella flexneri serotype 1b and shows the most common repeating unit. It has a role as an antigen.
[(2S,3R,4R,5S,6S)-2-[(2S,3R,4R,5R,6S)-2-[(2S,3R,4R,5S,6S)-2-[(2R,3R,4R,5S,6R)-3-acetamido-2-hydroxy-6-(hydroxymethyl)-5-[(2R,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxyoxan-4-yl]oxy-3-acetyloxy-5-hydroxy-6-methyloxan-4-yl]oxy-4,5-dihydroxy-6-methyloxan-3-yl]oxy-3,5-dihydroxy-6-methyloxan-4-yl] acetate