title: The C-terminal domain of the Bordetella pertussis autotransporter BrkA forms a pore in lipid bilayer membranes.
abstract: BrkA is a 103-kDa outer membrane protein of Bordetella pertussis that mediates resistance to antibody-dependent killing by complement. It is proteolytically processed into a 73-kDa N-terminal domain and a 30-kDa C-terminal domain as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. BrkA is also a member of the autotransporter family of proteins. Translocation of the N-terminal domain of the protein across the outer membrane is hypothesized to occur through a pore formed by the C-terminal domain. To test this hypothesis, we performed black lipid bilayer experiments with purified recombinant protein. The BrkA C-terminal protein showed an average single-channel conductance of 3.0 nS in 1 M KCl. This result strongly suggests that the C-terminal autotransporter domain of BrkA is indeed capable of forming a pore.
authors.affiliation: Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3.
authors.forename: J L
authors.initials: JL
authors.lastname: Shannon
authors.forename: R C
authors.initials: RC
authors.lastname: Fernandez
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D001886:Bordetella pertussis / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli; D008051:Lipid Bilayers; D008081:Liposomes; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D015183:Restriction Mapping; D013045:Species Specificity
chemical_list: D001425:Bacterial Outer Membrane Proteins; C090007:BrkA protein, Bordetella pertussis; D008051:Lipid Bilayers; D008081:Liposomes; D010446:Peptide Fragments; D011994:Recombinant Proteins