Structure of the Sialylated L3 Lipopolysaccharide of Neisseria Meningitidis

The L3 immunotype lipopolysaccharide (LPS) of Neisseria meningitidis was subjected to degradation procedures, which produced a number of different oligosaccharide fragments. The high resolution 1H and 13C NMR spectroscopic analyses of these oligosaccharides yielded structural information on a number of different regions of the LPS. For example, from one oligosaccharide, it was found that the endogenous sialylation of the meningococcal LPS occurs at O-3 of the terminal beta-D-galactopyranosyl residue of its lacto-N-neotetraose antenna in the alpha-D-configuration. From another, it was also established that the dominant structural feature responsible for L3 epitope specificity is the presence of a phosphorylethanolamine substituent at O-3 of the penultimate heptopyranosyl residue of its other antenna. In addition from information obtained with another oligosaccharide the structure of the 3-deoxy-D-manno-octulosonic acid disaccharide region of the L3 LPS was also elucidated. From all the above cumulative data plus some published data, it was then possible to reconstruct the complete structure of the entire native L3 LPS.