title: Polymorphic outer-membrane proteins of Chlamydophila abortus are glycosylated.
abstract: Antigenic profiles of mono-, bi- and poly-specific monoclonal antibodies against 90 kDa polymorphic outer-membrane proteins (POMPs) and a 105 kDa POMP-related protein of Chlamydophila abortus ATCC VR 656(T), after one- and two-dimensional electrophoretic analysis, helped identify each one of the triplets POMP 90, 91A and 91B, and a POMP-related protein at 85 kDa. The lectin concanavalin A bound to the four POMPs and the POMP-related protein in a specific manner and the binding was sensitive to treatment with the amidase N-endoglycosidase F, suggesting the presence of small asparagine-linked oligosaccharide chains. The exposure of the five proteins on the chlamydial surface and the orientation of the attached oligosaccharide chains was examined by protease and endoglycosidase treatments of intact bacteria. The results were consistent with the concept that some of the oligosaccharides in the POMPs face outwards, possibly protecting the polypeptides from proteolytic enzymes, whereas the oligosaccharides in the 105 kDa POMP-related protein are oriented inwards, thereby rendering the polypeptide chain accessible to proteases. A possible role for the N-linked oligosaccharides in the POMPs might be the promotion of the proper folding and processing of these proteins.
authors.affiliation: Department of Microbiology, Hellenic Pasteur Institute, Vassilissis Sofias 127, Athens 11521, Greece. vretou@mail.pasteur.gr
authors.forename: E
authors.initials: E
authors.lastname: Vretou
authors.forename: P
authors.initials: P
authors.lastname: Giannikopoulou
authors.forename: E
authors.initials: E
authors.lastname: Psarrou
mesh_terms: D000581:Amidohydrolases / Q000378:metabolism; D000907:Antibodies, Bacterial; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D016764:Cell Polarity; D023501:Chlamydophila / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D010450:Endopeptidases / Q000378:metabolism; D006023:Glycoproteins / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D006031:Glycosylation; D009844:Oligosaccharides / Q000378:metabolism; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase; D011110:Polymorphism, Genetic
chemical_list: D000907:Antibodies, Bacterial; D001425:Bacterial Outer Membrane Proteins; D006023:Glycoproteins; D009844:Oligosaccharides; D010450:Endopeptidases; D000581:Amidohydrolases; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase