title: Production of Bacillus anthracis protective antigen is dependent on the extracellular chaperone, PrsA.
abstract: Protective antigen (PA) is a component of the Bacillus anthracis lethal and edema toxins and the basis of the current anthrax vaccine. In its heptameric form, PA targets host cells and internalizes the enzymatically active components of the toxins, namely lethal and edema factors. PA and other toxin components are secreted from B. anthracis using the Sec-dependent secretion pathway. This requires them to be translocated across the cytoplasmic membrane in an unfolded state and then to be folded into their native configurations on the trans side of the membrane, prior to their release from the environment of the cell wall. In this study we show that recombinant PA (rPA) requires the extracellular chaperone PrsA for efficient folding when produced in the heterologous host, B. subtilis; increasing the concentration of PrsA leads to an increase in rPA production. To determine the likelihood of PrsA being required for PA production in its native host, we have analyzed the B. anthracis genome sequence for the presence of genes encoding homologues of B. subtilis PrsA. We identified three putative B. anthracis PrsA proteins (PrsAA, PrsAB, and PrsAC) that are able to complement the activity of B. subtilis PrsA with respect to cell viability and rPA secretion, as well as that of AmyQ, a protein previously shown to be PrsA-dependent.
authors.affiliation: School of Cell and Molecular Biosciences, The Medical School, University of Newcastle upon Tyne, Newcastle upon Tyne, NE2 4HH, United Kingdom.
authors.forename: Rachel C
authors.initials: RC
authors.lastname: Williams
authors.forename: Mark L
authors.initials: ML
authors.lastname: Rees
authors.forename: Myra F
authors.initials: MF
authors.lastname: Jacobs
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Prágai
authors.forename: Joanne E
authors.initials: JE
authors.lastname: Thwaite
authors.forename: Leslie W J
authors.initials: LW
authors.lastname: Baillie
authors.forename: Peter T
authors.initials: PT
authors.lastname: Emmerson
authors.forename: Colin R
authors.initials: CR
authors.lastname: Harwood
mesh_terms: D000595:Amino Acid Sequence; D000942:Antigens, Bacterial; D001408:Bacillus anthracis / Q000378:metabolism; D001412:Bacillus subtilis / Q000378:metabolism; D001426:Bacterial Proteins; D001427:Bacterial Toxins / Q000737:chemistry / Q000378:metabolism*; D015153:Blotting, Western; D004247:DNA / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D005816:Genetic Complementation Test; D016680:Genome, Bacterial; D007544:Isopropyl Thiogalactoside / Q000494:pharmacology; D008074:Lipoproteins / Q000378:metabolism / Q000502:physiology*; D008565:Membrane Proteins / Q000378:metabolism / Q000502:physiology*; D008969:Molecular Sequence Data; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D017510:Protein Folding; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D013997:Time Factors; D000516:alpha-Amylases / Q000737:chemistry / Q000378:metabolism
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D008074:Lipoproteins; D008565:Membrane Proteins; C030325:anthrax toxin; C082160:prsA protein, bacteria; D007544:Isopropyl Thiogalactoside; D004247:DNA; D000516:alpha-Amylases