STRUCTURE OF THE O6 ANTIGEN OF STENOTROPHOMONAS (XANTHOMONAS OR PSEUDOMONAS) MALTOPHILIA

A polysaccharide containing D-xylose, L-rhamnose, and N-acetyl-D-gluco samine was released on mild acid hydrolysis of the lipopolysaccharide extracted from defatted cell walls of Stenotrophomonas (Xanthomonas or Pseudomonas) maltophilia strain 557, the reference strain for serotyp e 06. By means of NMR spectroscopy and chemical degradations, the repe ating unit of the polymer was identified as a branched trisaccharide w ith the structure shown. GRAPHICS d B, and one minor, C. GRAPHICS A R(1) = beta-D-Glcp-(1 --> 4); R(2) = beta-D-Glcp-(1 --> 4)-alpha-D-G lcp-(1 --> 3) B R(1) = H; R(2) = beta-D-Glcp-(1 --> 4)-alpha-D-Glcp-(1 --> 3) C R(1) = beta-D-Glcp-(1 --> 4); R(2) = H In the structure, PEA is phosphoethanolamine, and L-D-Hep is L-glycero-D-manno-heptose. Kdo exists in reduced anhydro forms. The carbohydrate backbone is the sam e as that proposed for the saccharide part of the major component from H. influenzae type b strain A2