Structure of the sugar-phosphate moiety of lipid A from lipooligosaccharide of Neisseria meningitidis group B, strain BC5S No. 125. Hydrolytic stability of phosphate and pyrophosphate substituents.

On the basis of chemical and NMR data the partial structure of lipid A from lipooligosaccharide (LOS) of Neisseria meningitidis group B, strain BC5S No 125 was established. Lipid A consisted of disaccharide 2-deoxy-6-O-[2-deoxy-2-(3-hydroxytetradecanoylamino)- beta-gluco-pyranosyl]-2-(3-hydroxytetradecanoylamino)- alpha-glucopyranose carrying the beta-(2-aminoethyl)pyrophosphate residue at 0-4' and the pyrophosphate or phosphate residue at 0-1. On hydrolysis of the acidic form of LOS with 1% acetic acid the substituent at 0-1 was practically completely removed whereas that at 0-4' was stable. The analogous hydrolysis of the Mg-salt of LOS was accompanied by splitting off the pyrophosphate linkage in the substituent at 0-4'. Hydrolysis of LOS at pH 4.5 in the presence of SDS led mainly to a lipid A preparation retaining both pyrophosphate residues.