[3)-alpha-D-Galp-(1->3)-beta-D-Galf2Ac-(1->]n
[3)-alpha-d-galp-(1->3)-beta-d-galf2ac-(1->]n
A polysaccharide composed of a backbone of α-galactopyranosyl-(1→3)-galactofuranosyl repeating units that are joined to each other also via β-(1→3)-linkages; corresponds to the repeating unit of the <em>O</em>-specific polysaccharide from <em>Plesiomonas shigelloides</em> strain CNCTC 78/79, although in this species the <em>O</em>-acetylation is incomplete.