Structure of the neutral O-polysaccharide and biological activities of the lipopolysaccharide of Proteus mirabilis O20 Original Research Article

Mild acid degradation of the lipopolysaccharide (LPS) of Proteus mirabilis O20 resulted in depolymerisation of the O-polysaccharide to give a repeating-unit pentasaccharide. A polysaccharide was obtained by O-deacylation of the LPS followed by nitrous acid deamination. The derived pentasaccharide and polysaccharide were studied by NMR spectroscopy, including 2D 1H,1H COSY, TOCSY, ROESY, 1H,13C HMQC and HMQC–TOSCY experiments, along with chemical methods, and the following structure of the repeating unit of the O-polysaccharide was established: