The unique structure of bacterial polysaccharides - Immunochemical studies on the O-antigen of Proteus penneri 4034-85 clinical strain classified into a new O83 Proteus serogroup

Abstract

The serological classification scheme of the opportunistic Proteus bacilli includes a number of Proteus penneri strains. The tested P. penneri 4034-85 strain turned out to be serologically distinguished in ELISA and Western blotting. The O-polysaccharide was obtained by mild acid degradation of the lipopolysaccharide of this strain and studied by sugar and methylation analyses and dephosphorylation along with 1H and 13C NMR spectroscopy, including 2D 1H,1H COSY, TOCSY, ROESY, 1H,13C HSQC, HMBC, and HSQC-TOCSY experiments, The O-polysaccharide was found to have a linear repeating unit containing glycerol 1-phosphate and two residues each of Gal and GlcNAc. The following O-polysaccharide structure was established, which, to our knowledge, is unique among known bacterial polysaccharide structures:→4)-β-d-GlcpNAc-(1→3)-α-d-Galp-(1→3)-β-d-GlcpNAc-(1→2)-β-d-Galp-(1→3)-Gro-1-P-(O→.