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.
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J M
JM
Centre de Biochimie et de Biologie Moléculaire, CNRS, Marseilles, France.
Bolla
J M
JM
Bernadac
A
A
Fourel
D
D
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