title: Pertussis toxin export requires accessory genes located downstream from the pertussis toxin operon.
abstract: Pertussis toxin, a major virulence factor of Bordetella pertussis, is an oligomeric protein composed of five different subunits that are exported individually to the periplasmic space by the signal peptide-dependent pathway. After assembly, the protein is exported from the periplasm to the extracellular compartment. We show that pertussis toxin secretion across the outer membrane requires the gene product of at least one gene (ptlC) that is located downstream from the pertussis toxin operon. The amino acid sequence of PtlC shows a high degree of homology to VirB4, a protein encoded by the virB operon, which contains 11 open reading frames that are involved in the transfer of T-DNA from Agrobacterium tumefaciens to the plant cells. This is a novel mechanism of protein export in Gram-negative bacteria.
authors.affiliation: Immunobiology Research Institute Siena, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Covacci
authors.forename: R
authors.initials: R
authors.lastname: Rappuoli
mesh_terms: D016960:Agrobacterium tumefaciens / Q000235:genetics; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics; D001692:Biological Transport / Q000235:genetics; D001886:Bordetella pertussis / Q000235:genetics* / Q000378:metabolism; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D009876:Operon; D037342:Pertussis Toxin; D010641:Phenotype; D011499:Protein Processing, Post-Translational; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D037521:Virulence Factors; D010566:Virulence Factors, Bordetella / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D037521:Virulence Factors; D010566:Virulence Factors, Bordetella; D037342:Pertussis Toxin