The structure of the polysaccharide moiety of rhodopseudomonas sphaeroides atcc 17023 lipopolysaccharide

The chemical structure of the polysaccharide moiety of the lipopolysaccharide of Rhodopseudomonas sphaeroides ATCC 17023 was established. Mild acetic acid hydrolysis of isolated lipopolysaccharide, followed by preparative high-voltage paper electrophoresis afforded three oligosaccharides. They were characterized by chemical and physicochemical studies to be: GlcA(α14)dOclA8P, Thr(6′) GlcA(α14)GlcA and GlcA(α14)dOclA, where GlcA is d-glucuronic acid and dOclA is 3-deoxy-d-manno-octulosonic acid. Carboxyl-reduction of the lipopolysaccharide followed by acid hydrolysis gave a trisaccharide: GlcA(α14)Glc(α14)G1c, showing the presence of three residues of glucuronic acids in the O-specific chain and indicating that only two of them are reducible by NaBH4. The linkage between the polysaccharide and lipid A was shown to be through a single 1,4-linked residue of dOclA attached by a 2,6′-linkage to the lipid A moiety.