title: Structural analysis of lipooligosaccharide produced by Neisseria gonorrhoeae, strain MS11mk (variant A): a precursor for a gonococcal lipooligosaccharide associated with virulence.
abstract: We studied the structure of the lipooligosaccharide (LOS) that is produced by a variant A of strain MS11mk. This variant produces a single LOS that is recognized by monoclonal antibody (MAb) 2-1-L8. In a recent study of the pathogenesis of Neisseria gonorrhoeae in male volunteers, variant A gave rise to other phase variants that produce higher molecular weight LOSs, and these LOS were associated with virulence. Definition of the structure of the variant A LOS is important to understand the biosynthesis of LOS and its expression in vivo. The dephosphorylated oligosaccharide (OS) structure derived from the variant A LOS was analyzed by two-dimensional NMR and methylation analysis. The OS structure was found to be a truncated form of the LOS produced by strain F62 [Yamasaki et al. (1991) Biochemistry 30, 10566-10575]; the variant A OS is a hexamer, a beta-lactosyl residue linked to a tetrasaccharide: Gal beta 1-->4Glc beta 1-->4[GlcNAc alpha 1-->2Hep alpha 1-->3]Hep alpha 1-->KDO. We determined that the variant A LOS is a precursor for the synthesis of higher MW LOS. We also studied expression of the MAb 2-1-L8-defined epitope present on the variant A LOS. Our data indicate that the MAb-defined epitope is not a linear beta-lactosyl residue but its specificity is directed toward the phosphorylated GlcNAc-Hep-Hep residue. Since this MAb binds to gonococci, at least part of the phosphorylated diheptose area is exposed on the gonococcal surface.
mesh_terms: D000911:Antibodies, Monoclonal; D002240:Carbohydrate Sequence; D000939:Epitopes / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry; D014644:Genetic Variation; D008070:Lipopolysaccharides / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008745:Methylation; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009344:Neisseria gonorrhoeae / Q000378:metabolism* / Q000472:pathogenicity*; D010766:Phosphorylation; D011498:Protein Precursors / Q000737:chemistry*
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D008070:Lipopolysaccharides; D011498:Protein Precursors