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

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 H-1 and C-13 NMR spectroscopy, including 2D H-1,H-1 COSY, TOCSY, ROESY, H-1,C-13 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)-beta-D-GlcpNAc-(1 -> 3)-alpha-D-Galp-(1 -> 3)-beta-D-GlcpNAc-(1 -> 2)-beta-D-Galp-(1 -> 3)-Gro-1-P-(O ->. (C) 2020 Elsevier B.V. All rights reserved.