title: Structural determination of the sialic acid polysaccharide antigens of Neisseria meningitidis serogroups B and C with carbon 13 nuclear magnetic resonance.
abstract: The application of 13-C nuclear magnetic resonance to the analysis of some sialic acid-containing meningococcal polysaccharide antigens is described. Complete assignments of the spectra of both the native serogroup B and the de-O-acetylated serogroup C polysaccharides have been made. These assignments were based on the corresponding data for some related monomers (sialic acid and its alpha-and beta-methylglycosides) and on supportive chemical evidence. The data indicate that the serogroup B polysaccharide is a 2 yields 8-alpha-linked homopolymer of sialic acid, identical in structure with colominic acid from Escherichia coli, whereas the de-O-acetylated serogroup C polysaccharide is a 2 yield 9-alpha-linked homopolymer. The native serogroup C polysaccharide is O-acetylated (1.16 mol of O-acetyl per sialic acid residue), all the O-acetyl substituents being located only at C-7 and C-8 of the sialic acid residues, and in addition contains unacetylated residues (24%). The polysaccharide contains di-O-acetylated residues (O-acetyl on C-7 and C-8), and at least one of the possible monoacetylated residues at C-7 or C-8.
mesh_terms: D000942:Antigens, Bacterial; D002247:Carbon Isotopes; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D009345:Neisseria meningitidis / Q000276:immunology; D009439:Neuraminidase; D010504:Periodic Acid; D011134:Polysaccharides / Q000276:immunology; D012794:Sialic Acids / Q000276:immunology
chemical_list: D000942:Antigens, Bacterial; D002247:Carbon Isotopes; D011134:Polysaccharides; D012794:Sialic Acids; D010504:Periodic Acid; D009439:Neuraminidase