STRUCTURE OF THE SIALYLATED L3 LIPOPOLYSACCHARIDE OF NEISSERIA-MENINGITIDIS

The L3 immunotype lipopolysaccharide (LPS) of Neisseria meningitidis w as subjected to degradation procedures, which produced a number of dif ferent oligosaccharide fragments. The high resolution H-1 and C-13 NMR spectroscopic analyses of these oligosaccharides yielded structural i nformation on a number of different regions of the LPS. For example, f rom one oligosaccharide, it was found that the endogenous sialylation of the meningococcal LPS occurs at O-3 of the terminal beta-D-galactop yranosyl residue of its lacto-N-neotetraose antenna in the alpha-D-con figuration. From another, it was also established that the dominant st ructural feature responsible for L3 epitope specificity is the presenc e of a phosphorylethanolamine substituent at O-3 of the penultimate he ptopyranosyl residue of its other antenna. In addition from informatio n obtained with another oligosaccharide the structure of the 3-deoxy-D -manno-octulosonic acid disaccharide region of the L3 LPS was also elu cidated. From all the above cumulative data plus some published data, it was then possible to reconstruct the complete structure of the enti re native L3 LPS.