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Forward Genetic Approaches in Chlamydia trachomatis
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Polymorphic outer-membrane proteins of Chlamydophila abortus are glycosylated

E Vretou1, P Giannikopoulou, E Psarrou

  • 1Department of Microbiology, Hellenic Pasteur Institute, Vassilissis Sofias 127, Athens 11521, Greece. vretou@mail.pasteur.gr

Microbiology (Reading, England)
|December 12, 2001
PubMed

Insights

Monoclonal antibodies identified polymorphic outer-membrane proteins (POMPs) and related proteins in Chlamydophila abortus. N-linked oligosaccharides on POMPs face outward, potentially aiding protein folding and protection.

Area of Science:

  • Microbiology
  • Protein Chemistry
  • Glycobiology

Background:

  • Chlamydophila abortus possesses polymorphic outer-membrane proteins (POMPs) and related proteins crucial for its structure and function.
  • Understanding the antigenic profiles and glycosylation of these proteins is essential for characterizing Chlamydophila abortus.

Purpose of the Study:

  • To characterize the antigenic profiles of Chlamydophila abortus POMPs and a related protein using monoclonal antibodies.
  • To investigate the presence and orientation of N-linked oligosaccharide chains on these proteins and their potential roles.

Main Methods:

  • Electrophoretic analysis (one- and two-dimensional) to identify protein components.
  • Monoclonal antibody binding assays to determine antigenic profiles.
  • Lectin binding (concanavalin A) and enzymatic treatments (N-endoglycosidase F, proteases) to analyze oligosaccharide presence and orientation.

Main Results:

  • Identification of specific POMP triplets (90, 91A, 91B) and a POMP-related protein (85 kDa).
  • Concanavalin A specifically bound to these proteins, sensitive to N-endoglycosidase F, indicating N-linked oligosaccharides.
  • Protease and endoglycosidase treatments revealed outward-facing oligosaccharides on POMPs and inward-facing ones on the related protein.

Conclusions:

  • Chlamydophila abortus POMPs and a related protein possess N-linked oligosaccharides.
  • The orientation of these oligosaccharides differs, with POMP oligosaccharides potentially protecting the protein and facilitating folding, while the related protein's oligosaccharides are internally oriented.
  • These findings contribute to understanding the surface structure and potential virulence factors of Chlamydophila abortus.

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