Structure of the O-polysaccharide of Yersinia frederiksenii H56-36/81 (serotype O:60) containing 4-deoxy-d-arabino-hexose

Abstract

Aiming at creation of the chemical basis for serotyping of strains of Yersinia spp., we studied the O-specific polysaccharide (OPS) of Yersinia frederiksenii H56-36/81 belonging to serotype O:60. A branched polysaccharide was obtained by mild alkaline degradation of the lipopolysaccharide (LPS) isolated from bacterial cells by the phenol—water extraction and found to contain d-ribose, l-rhamnose, and 4-deoxy d-arabino-hexose (d-ara4dHex). The last monosaccharide occurs rarely in nature and earlier has been found only in OPS of Citrobacter spp. Mild acid hydrolysis of the LPS resulted in cleavage of the d-ara4dHex side-chains to give a linear polysaccharide. Structure of the hexasaccharide repeating unit of the OPS was established by studies of both isolated polysaccharides by 1D and 2D ¹H and ¹³C NMR spectroscopy.