Structural analysis of the lipopolysaccharide from Chlamydophila psittaci strain 6BC

The lipopolysaccaride of Chlamydophila psittaci 6BC was isolated from tissu e culture-grown elementary bodies using a modified phenol/water procedure f ollowed by extraction with phenol/chloroform/light petroleum. Compositional analyses indicated the presence of 3-deoxy-D-manno-oct-2-ulosonic acid, Gl cN, organic bound phosphate and fatty acids in a molar ratio of approximate to 3.3 : 2 : 1.8 : 4.6. Deacylated lipopolysaccharide was obtained after s uccessive microscale treatment with hydrazine and potassium hydroxide, and was then separated by high performance anion-exchange chromatography into t wo major fractions, the structures of which were determined by 600MHz NMR s pectroscopy as alpha-Kdo-(2-->8)-alpha-Kdo-(2-->4)-alpha-Kdo-(2-->6)-beta-D -GlcpN-(1-->6)-alpha-D- GlcpN 1,4'-bisphosphate and alpha-Kdo-(2-->4)-[alph a-Kdo-(2-->8)]-alpha-Kdo-(2-->4)-alpha-Kdo-(2-->6)-beta-D-GlcpN-(1-->6)-alp ha-D-GlcpN 1,4'-bisphosphate. The distribution of fatty acids in lipid A wa s determined by compositional analyses and matrix-assisted laser desorption /ionization time-of-flight mass spectrometry experiments on lipid A and de- O-acylated lipid A. It was shown that the carbohydrate backbone of lipid A is replaced by a complex mixture of fatty acids, including long-chain and b ranched (R)-configured 3-hydroxy fatty acids, the latter being exclusively present in an amide linkage.