Structural studies of the O-specific polysaccharide from Plesiomonas shigelloides strain CNCTC 113/92

The structure of the O-specific side chain of the lipopolysaccharide (LPS) of Plesiomonas shigelloides, strain CNCTC 113/92 has been investigated by NMR spectroscopy, matrix-assisted laser desorption/ionization time of flight mass spectrometry and sugar and methylation analysis. It was concluded that the polysaccharide is composed of a hexasaccharide repeating unit with the following structure: [GRAPHICS] in which D-beta-D-Hepp is D-glycero-beta-D-manno-heptopyranose and 6d-beta-d-Hep is 6-deoxy-beta-D-manno-heptopyranose. This structure represents a novel hexasaccharide repeating unit of bacterial O-antigen that is characteristic and unique to the Plesiomonas shigelloides strain. Using the high-resolution magic angle spinning technique, H-1-NMR spectra were also obtained for the O-polysaccharide components of isolated LPS and in their original form directly on the surface of bacterial cells.