Structure of O specific side chains of lipopolysaccharides from Yersinia pseudotuberculosis

Abstract

Lipopolysaccharide prepared from cells of Yersinia (Pasteurella) pseudotuberculosis of serogroups I, II, III, IV, and V is known to contain the 3, 6 dideoxyhexose (DDH) paratose, abequose, paratose, tyvelose, and ascarylose in its respective O specific side chains. Lipopolysaccharides or lipid free polysaccharides of all of the 10 known serogroups and subgroups were subjected to methylation analysis and determined as alditol acetates by gas liquid chromatography and mass spectrometry. The results indicated that the O specific side chains of nine serotypes are composed of oligosaccharide repeating units in the form of four alternative general structures in which a terminal DDH may vary. These structures are DDH → 6 deoxy D manno heptose → D galactose (serogroups IA, IIA, and IVB), DDH → D mannose → L fucose (serogroups IB and IIB), and two configurations similar to the latter except that the 4 position of L fucose was either linked to the D mannose residue (serogroups VA and VB) or to the DDH residue (serogroups III and IVA). In contrast, O groups in lipopolysaccharide of the newly discovered serogroup VI contained the DDH colitose and 2 acetamido 2 deoxy D galactose. Accordingly, all five known types of DDH have now been detected in lipopolysaccharides of Y. pseudotuberculosis. The sugar 6 deoxy D manno heptose, present in O specific side chains of serogroups IA, IIA, and IVB, has not yet been reported to occur elsewhere in nature.