Lipopolysaccharides from Yersinia pestis

The chemical structure of the lipid A of lipopolysaccharide I and II from Yersinia pestis, strain EV 40, was studied. It consists of a (1 ---- 6), beta-linked D-glucosamine disaccharide which carries two phosphate groups; one phosphate is linked glycosidically with a glucosamine unit, the other one is linked to the non-reducing glucosamine. Various degradation methods combined with 31P nuclear magnetic resonance spectroscopy showed that the ester-bound phosphate group is linked to a 4-aminoarabinosyl residue and the glycosidically linked phosphate group is linked to a D-arabinofuranosyl residue in lipopolysaccharide II and to the phosphorylethanolamine in lipopolysaccharide I. The hydroxyl groups of the disaccharide are acylated by dodecanoic, hexadecenoic, 3-hydroxytetradecanoic and 3-dodecanoyloxytetradecanoic acids. The amino groups of the disaccharide carry 3-hydroxytetradecanoic and 3-dodecanoyloxytetradecanoic acids. In addition smaller amounts of 3-tetradecanoyloxyltetradecanoic and 3-hexadecanoyloxytetradecanoic acids are present in ester linkage.