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->3) linkage of an alpha-D-glucosyl group to the Rha(II) residue and by addition of an acetyl group to either O-3 or O-4 of many of the Rha(III) residues (35% to O-3; 25% to O-4). The structure provided is representative of that in Shigella flexneri serotype 5a and shows the most common repeating unit. It has a role as an antigen.
[(2S,3R,4R,5S,6S)-2-[(2S,3R,4R,5S,6S)-2-[(2S,3R,4R,5S,6S)-2-[(2R,3R,4R,5S,6R)-3-acetamido-2,5-dihydroxy-6-(hydroxymethyl)oxan-4-yl]oxy-3,5-dihydroxy-6-methyloxan-4-yl]oxy-5-hydroxy-6-methyl-4-[(2R,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxyoxan-3-yl]oxy-3,5-dihydroxy-6-methyloxan-4-yl] acetate