Structural elucidation of the O-antigen lipopolysaccharide from two strains of Plesiomonas shigelloides that share a type-specific antigen with Shigella flexneri 6, and the common group 1 antigen with Shigella flexneri spp and Shigella dysenteriae 1

Abstract

Sugar and methylation analyses of native polysaccharides together with one-dimensional 1H- and 13C-NMR spectroscopy revealed that the two polysaccharides from strains 22074 and 12254 of Plesiomonas shigelloides are identical. The structure of the polysaccharide from strain 22074 was deduced from a uronic acid degradation and by NMR spectroscopy where heteronuclear multiple bond connectivity and two-dimensional nuclear Overhauser effect spectroscopy experiments established the pentasaccharide repeating unit as-->4)-alpha-D-GalpA-(1-->3)-alpha-D-GlcpNAc-(1-->3)-alpha-L- Rhap-(1-->2)-alpha-L-Rhap-(1-->2)-alpha-L-Rhap-(1-->