title: An N-linked high-mannose type oligosaccharide, expressed at the major outer membrane protein of Chlamydia trachomatis, mediates attachment and infectivity of the microorganism to HeLa cells.
abstract: The structure of the carbohydrate of the 40-kD major outer membrane component of Chlamydia trachomatis and its role in defining infectivity of the organism were investigated. The oligosaccharides were released from the glycoprotein by N-glycanase digestion, coupled to a 2-aminopyridyl residue, and subjected to two-dimensional sugar mapping technique. The major fractions consisted of "high-mannose type" oligosaccharides containing 8-9 mannose residues. Bi- and tri-antennary "complex type" oligosaccharides having terminal galactose were detected as minor components. These oligosaccharides were N-linked and contained no sialic acid. This structural profile is consistent with our previous characterization based on lectin-binding and glycosidase digestion. Functional specificity of identified chlamydial oligosaccharides was analyzed using glycopeptides fractionated from ovalbumin and structurally defined oligosaccharides from other sources. The glycopeptide fraction having high-mannose type oligosaccharide, as compared to those having complex or hybrid-type, showed a stronger inhibitory effect on attachment and infectivity of chlamydial organisms to HeLa cells. Among high-mannose type oligosaccharides, the strongest inhibition was observed with mannose 8 as compared with mannose 6, 7, or 9. These results indicate that a specific high-mannose type oligosaccharide linked to the major outer membrane protein of C. trachomatis mediates attachment and infectivity of the organism to HeLa cells.
authors.affiliation: Department of Pathobiology, University of Washington, Seattle 98195, USA. cckuo@u.washington.edu
authors.forename: C
authors.initials: C
authors.lastname: Kuo
authors.forename: N
authors.initials: N
authors.lastname: Takahashi
authors.forename: A F
authors.initials: AF
authors.lastname: Swanson
authors.forename: Y
authors.initials: Y
authors.lastname: Ozeki
authors.forename: S
authors.initials: S
authors.lastname: Hakomori
mesh_terms: D000581:Amidohydrolases / Q000378:metabolism; D001422:Bacterial Adhesion / Q000187:drug effects; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000494:pharmacology; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002692:Chlamydia trachomatis / Q000737:chemistry*; D002845:Chromatography; D002846:Chromatography, Affinity; D006020:Glycopeptides / Q000494:pharmacology; D006367:HeLa Cells; D006801:Humans; D008362:Mannosides / Q000494:pharmacology; D008969:Molecular Sequence Data; D015394:Molecular Structure; D010047:Ovalbumin / Q000737:chemistry; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase; D011135:Polysaccharides, Bacterial / Q000737:chemistry* / Q000494:pharmacology; D018272:Porins
chemical_list: D001425:Bacterial Outer Membrane Proteins; D006020:Glycopeptides; D008362:Mannosides; D011135:Polysaccharides, Bacterial; D018272:Porins; C071677:omp1 protein, Chlamydia trachomatis; D010047:Ovalbumin; D000581:Amidohydrolases; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase