Importance of holotoxin assembly in Ptl-mediated secretion of pertussis toxin from Bordetella pertussis.
We examined the structural components of pertussis toxin that are required for efficient export from Bordetella pertussis via the Ptl system, a member of the type IV family of macromolecular transporters. First, we constructed a strain of B. pertussis that contains a functional Ptl system but does not produce pertussis toxin. Plasmids which express either the S1 subunit or the B oligomer were then introduced into this strain. We found that the B oligomer of the toxin is not secreted in the absence of the S1 subunit. Conversely, the S1 subunit is also not secreted by a Ptl-mediated mechanism in the absence of the B oligomer. Thus, an assembled holotoxin is required for Ptl-mediated export of pertussis toxin from B. pertussis.
Farizo
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KM
Division of Bacterial, Parasitic, and Allergenic Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland 20892, USA. farizo@cber.fda.gov
Huang
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T
Burns
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DL
D001483:Base Sequence; D001693:Biological Transport, Active; D001886:Bordetella pertussis / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D017931:DNA Primers / Q000235:genetics; D005798:Genes, Bacterial; D037342:Pertussis Toxin; D010957:Plasmids / Q000235:genetics; D020836:Protein Structure, Quaternary; D017384:Sequence Deletion; D014774:Virulence; D010566:Virulence Factors, Bordetella / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D017931:DNA Primers; D010566:Virulence Factors, Bordetella; D037342:Pertussis Toxin