STRUCTURAL INVESTIGATION OF THE LIPOPOLYSACCHARIDE FROM ACINETOBACTER-HAEMOLYTICUS STRAIN NCTC-10305 (ATCC-17906, DNA GROUP-4)

The structure of the lipopolysaccharide (LPS) from Acinetobacter haemo lyticus strain NCTC 10305 (DNA group 4) was elucidated by means of ana lytical chemistry, NMR spectroscopy and fast-atom-bombardment mass spe ctrometry, Several oligosaccharides were obtained after deacylation or successive de-O-acylation, dephosphorylation, reduction, and de-N-acy lation of LPS. In the major fraction of the LPS, the core is attached to the lipid A through D-glycero-D-talo-2-octulopyranosonic acid (Ko), whereas in a minor fraction (<20%) Ko is replaced by 3-deoxy-D-manno- octulopyranosonic acid (Kdo). The structures of the phosphorylated car bohydrate backbones of these LPS fractions are [GRAPHICS] lc6P-(1-5)-a lpha-Sug-(2-6)-beta-GlcN4P-(1-6)-alpha GlcN1P with Dha = 3-deoxy-D-lyx o-2-heptulosaric acid, Sug = sugar and is Ko in a major fraction and K do in a minor fraction. All sugar residues have the D-configuration an d are present in the pyranose form. Mass spectrometry of de-O-acylated LPS revealed the presence of an additional hexose residue in minor am ounts, the position and nature of which could not be identified.