Structural determination of the group K capsular polysaccharide of Neisseriameningitidis: a 2D-NMR analysis

Abstract

. 63, 2781 (1985).The capsular polysaccharide antigen of Neisseria meningitidis group K was isolated by Cetavlon precipitation and purified by ion-exchange chromatography. The structure of the K plysaccharide was determined to a large extent by comprehensive proton and carbon-13 nuclear magnetic resonance (nrnr) studies. In these studies one-dimensional and two-dimensional experiments were carried out directly on the K polysaccharide. The K polysaccharide is composed of the following repeating unit: -4)P-D-ManpNAcA(1-+3) [4-OAc]P-D-ManpNAcA(l+. Except for the one-bond couplings between their anomeric carbons and protons ( I J I )~,~) , all the nmr spectroscopic evidence was consistent with both 2-acetamido-2-deoxy-D-mannopyranosyluronic acid residues adopting the 4~1 (D) conformation and having the P-D-configuration. This ambiguity in ' J I~~,~ is probably due to through-space electronic effects generated by the presence of contiguous carboxylated sugar residues in the K plysaccharide. The 0-acetyl substituents of the K polysaccharide are essential for its antigenicity to group K polysaccharide-specific antibodies.

Structural determination of the capsular polysaccharide of Neisseria meningitidis group I: a two-dimensional NMR analysis

“…Residue B is also a constituent of the de-O-acetylated meningococcal K polysaccharide which has the repeating unit -*•4)ß--3 /? (1-*•3)ß--ManpNAcA(l-* (Michon et al, 1985). In this environment, residue B and the 4-linked ß-D-mannuronopyranosyl residue both have glycosidically linked hexuronopyranosyl residues, and both exhibit similar and anomalous Vi3C H values (171.0 and 168.8 Hz, respectively).…”

“…Therefore, the distance between the carboxylate group of residue A and the anomeric proton of residue B must be greater than the equivalent distance between the same groups on residues B and A, respectively. This distance is dependent on the orientation of these glycosidic linkages, and as such, the orientation of the glycosidic linkage between residues B and A of the I polysaccharide differs substantially from that between residues A and B of the same polysaccharide, and also from the orientation of both glycosidic linkages between the two 2-acetamido-2-deoxy^-D-mannuronopyranosyl residues of the K polysaccharide (Michon et al, 1985).…”

“…As a continuation of our structural studies on the meningococcal polysaccharides, we now report the structure of the I polysaccharide. The structure of the K polysaccharide has been reported elsewhere (Michon et al, 1985).…”

“…Nuclear magnetic resonance spectroscopy has played an increasingly important role in the structural elucidation of the meningococcal polysaccharides (Jennings, 1983;Jennings et al, 1983;Michon et al, 1984;Van der Kaaden et al, 1984), and the utility of this technique has been further demonstrated in the structural elucidation of the K (Michon et al, 1985) and I polysaccharides, where a number of one-dimensional and 0006-2960/85/0424-5592S01.50/0 © 1985 American Chemical Society two-dimensional, including nuclear Overhauser enhancement (NOE), techniques were employed. Although two-dimensional techniques (Patt, 1984) have been used frequently on oligosaccharides since they were first reported in 1982 (Bernstein & Hall, 1982; Prestegard et al, 1982; Bruch & Bruch, 1982), examples of the direct application of these techniques to polysaccharides are few (Barrow et al, 1984).…”

Structure of the complex group-specific polysaccharide of group B Streptococcus

“…The most convincing evidence in favor of all the rhamnopyranosyl residues in III having the -L configuration was (Átained from the proton-coupled 13C NMR spectrum of III. Vuqh coupling constants are sensitive to change in anomeric configuration (Perlin et al, 1970), and those of the Lrhamnopyranosyl residues in III (Table IV) are characteristic of all the L-rhamnopyranosyl residues being in the -L configuration.…”