Immunological approach of assembly and topology of OmpF, an outer membrane protein of Escherichia coli.
Various monoclonal antibodies (MoF) directed against cell-surface-exposed epitopes of OmpF, one major outer membrane pore protein of Escherichia coli B and K-12, have been used to study the assembly and the topology of the protein. This paper firstly describes the characterization of the OmpF epitopes recognized by the various monoclonal antibodies. A comparison between OmpC, OmpF and PhoE porins with respect to their primary amino acid sequence and their cell-surface exposed regions allows us to propose a rough model including 2 antigenic sites. The second part is focused on the assembly of the OmpF protein in the outer membrane. Various forms, precursor, unassembled monomer, metastable oligomer (pre-trimer) and trimer are detected with immunological probes directed against OmpF during a kinetic analysis of the process. The requirement for a concomitant lipid synthesis during the trimerization has been demonstrated by investigating the presence of a specific native epitope. The role of lipopolysaccharide during the stabilization of the conformation is discussed with regard to the various steps of assembly.
Centre de Biochimie et de Biologie Moléculaire, CNRS, Marseilles, France.
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Bolla
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Bernadac
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Fourel
D000907:Antibodies, Bacterial / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000276:immunology; D000942:Antigens, Bacterial / Q000276:immunology; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D000939:Epitopes / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D007473:Ion Channels / Q000276:immunology / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000378:metabolism; D011487:Protein Conformation; D011498:Protein Precursors / Q000378:metabolism; D011499:Protein Processing, Post-Translational
D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D000939:Epitopes; D007473:Ion Channels; D008070:Lipopolysaccharides; D011498:Protein Precursors