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

J Clin Invest. 1996 Dec 15;98(12):2813-8. doi: 10.1172/JCI119109.


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.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amidohydrolases / metabolism
  • Bacterial Adhesion / drug effects
  • Bacterial Outer Membrane Proteins / chemistry*
  • Bacterial Outer Membrane Proteins / pharmacology
  • Carbohydrate Conformation
  • Carbohydrate Sequence
  • Chlamydia trachomatis / chemistry*
  • Chromatography
  • Chromatography, Affinity
  • Glycopeptides / pharmacology
  • HeLa Cells
  • Humans
  • Mannosides / pharmacology
  • Molecular Sequence Data
  • Molecular Structure
  • Ovalbumin / chemistry
  • Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase
  • Polysaccharides, Bacterial / chemistry*
  • Polysaccharides, Bacterial / pharmacology
  • Porins*


  • Bacterial Outer Membrane Proteins
  • Glycopeptides
  • Mannosides
  • Polysaccharides, Bacterial
  • Porins
  • omp1 protein, Chlamydia trachomatis
  • Ovalbumin
  • Amidohydrolases
  • Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase