S. flexneri serotype 2a O-polysaccharide (O factor 9-negative)
s. flexneri serotype 2a o-polysaccharide (o factor 9-negative)
A polysaccharide derivative comprised of a [2)-α-<small>L</small>-Rha<em>p</em><small><sup>III</small></sup>-(1→2)-α-<small>L</small>-Rha<em>p</em><small><sup>II</small></sup>-(1→3)-α-<small>L</small>-Rha<em>p</em><small><sup>I</small></sup>-(1→3)-β-<small>D</small>-Glc<em>p</em>NAc-(1→] tetrasaccharide repeat modified by the (1→4) linkage of an α-<small>D</small>-glucosyl group to the Rha<small><sup>I</small></sup> residue and by addition of an acetyl group to 50% of the O-6 positions of the GlcNAc residue. The structure provided is representative of that in <em>Shigella flexneri</em> serotype 2a and shows the repeating unit containing the acetyl group on the GlcNAc residue.