Neisseria meningitidis structure

Similar reasoning (see Table IX) showed that the structure of the non-O-acetylated polysaccharide of Neisseria meningitidis serogroup W135 (for its 13C-n.m.r. spectrum, see Fig. 35,C) is closely related, containing D-galactopyranosyl in place of D-glucopyranosyl residues (in 33). 

Observation of displacement effects resulting from O-substitution, and use of standards, led to the assignment of the chemical structure of the polysaccharide of Neisseria meningitidis serogroup 29e, which consists of 2-acetamido-2-deoxy-D-galactosyl and partly acetylated 3-deoxy-D-manno-octulosylonic acid (KDO) residues.166 The 13C-n.m.r. spectrum of the O-deacetylated polymer (see Fig. 36,B) contained 15 signals out of the possible 16 expected from an alternating structure. Comparison of these resonances with those of the anomers of 2-aceta-... 

The first report of the occurrence of KDO in a structure other than LPS was that of Taylor47 on the capsular polysaccharide (K-antigen) of a clinical isolate, Escherichia coli LP1092. Almost simultaneously, Bhattachaijee and coworkers83 described an exopolysaccharide from Neisseria meningitidis serogroup 29e. This material contains KDO... 

Fig. 6.—Chemical structure of the lipid A backbone of Neisseria meningitidis M986 LPS having polar substituents. The nonglycosylic and glycosylic phosphate groups are substituted by Etn-P to a similar degree (85 vs 80%, w/w). The anomeric configuration of the phosphate has been assigned tentatively as a. R1 = 12 0(3-OH), R2 = 14-O[12 0(3-OH)] (73).

Not all capsular polysaccharides of uropathogenic and invasive coli bacteria contain KDO. Some of the non-KDO capsular polysaccharides are shown in Figure 12 (11-16). These are the Kl, K2, K5 and K51 polysaccharides. The Kl polysaccharide is a poly-a-2.8-N-acetyl-neuraminic acid and has been known as colominic acid since many years (11). Its structure which is identical with that of the capsular antigen of Neisseria meningitidis B has first been reported by McGuire and Binkley... 

Bhattacharjee, A.K., Jennings, H.J., Kenny, C.P., Martin, A. and Smith I.C.P. (1975) Structural determination of the sialic polysaccharide antigens of Neisseria meningitidis serogroup B and C with carbon 13 nuclear magnetic resonance. J. Biol. Chem. 250 1926-1932... 

SCHEME 14.12 Synthesis of core structure of LPS from Neisseria meningitidis. Bz, benzoyl NBS, A -bromosuccinimide PBB,/)-bromobenzyl. 

Fig. 6. —Structure of the Group C (uppermost), B (middle), and Terminally Reduced Group A (lowest) Polysaccharide Antigens of Neisseria meningitidis, Depicting the Positions of Cleavage on Oxidation by Periodate.

Fig. 3. Generalised structure of the dephosphorylated Neisseria meningitidis oligosaccharide part of the LPS...

The meningococcus, Neisseria meningitidis, is divided into 10 distinct serotypes. Groups B and C are responsible for 80% of the meningitis cases reported, one of the major causes of death in children and adults. These bacteria contain linear polysialic acids. In Group C, the bond between the sialyl residues, partially or non-acetylated, is a-(2->9). This structure, 12.26, is a powerful immunogen the polysaccharide of Group C is an official vaccine. However, there is no response in children less than two years old, perhaps because at this age, a similar polysialyl structure is found in their tissues. 

Prince SM, Achtman M, Derrick JP (2002) Crystal structure of the opcA integral membrane adhesin from Neisseria meningitidis. Proc Natl Acad Sci USA 99 3417-3421... 

Scheme 2 Structure of the core region from Neisseria meningitidis BZ157 B5- - showing the presence of isomeric giycoforms. Hex, hexose Hep, heptose Kdo, 3-deoxy-o-manno-octuiosonic acid GicN, giucosamine HexNAc, W-acetyihexosamine PEtn, phosphoethanoiamine PPEtn, pyrophosphoethanoiamine.

Scheme 3 Derived structure of core region from Neisseria meningitidis strain NGH15. Hex, hexose HexNAc, N-acetyihexosamine Hep, heptose Kdo, 3-deoxy-D-manno-octuiosonic acid Giy, giycine PEtn, phosphoethanoiamine Ac, acetic acid.

Figure 3 Representative structures for GT-A and GT-B folds. GT-A Family 2, SpsA enzyme from Bacillus subtilis (PDB 1QG8) GT-B Family 8, a-galactosyltransferase LgtC from Neisseria meningitidis 126E (PDB 1G9R).

FIGURE 7.8 Structure of the conserved inner core oligosaccharide regions of LPS from N. meningitidis and H. influenzae. (A) Haemophilus influenzae capsular and noncapsular strains. (B) Neisseria meningitidis strain. (Adapted from Li, J. et al. Methods Enzymol, 405, 369, 2005. With permission.)... 

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