title: Lytic activity of the Vibrio cholerae type VI secretion toxin VgrG-3 is inhibited by the antitoxin TsaB.
abstract: The type VI secretion system (T6SS) of Gram-negative bacteria has been implicated in microbial competition; however, which components serve purely structural roles, and which serve as toxic effectors remains unresolved. Here, we present evidence that VgrG-3 of the Vibrio cholerae T6SS has both structural and toxin activity. Specifically, we demonstrate that the C-terminal extension of VgrG-3 acts to degrade peptidoglycan and hypothesize that this assists in the delivery of accessory T6SS toxins of V. cholerae. To avoid self-intoxication, V. cholerae expresses an anti-toxin encoded immediately downstream of vgrG-3 that inhibits VgrG-3-mediated lysis through direct interaction.
authors: Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada T6G 2S2.
authors: Teresa M
authors: TM
authors: Brooks
authors: Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada T6G 2S2.
authors: Daniel
authors: D
authors: Unterweger
authors: Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada T6G 2S2.
authors: Verena
authors: V
authors: Bachmann
authors: Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada T6G 2S2.
authors: Benjamin
authors: B
authors: Kostiuk
authors: Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada T6G 2S2. Electronic address: spukatzki@ualberta.ca.
authors: Stefan
authors: S
authors: Pukatzki
mesh_terms: D000992:Antitoxins / Q000378:metabolism* / Q000502:physiology; D001426:Bacterial Proteins / Q000378:metabolism* / Q000502:physiology*; D058947:Bacterial Secretion Systems / Q000502:physiology*; D002473:Cell Wall / Q000378:metabolism; D003001:Cloning, Molecular; D019295:Computational Biology / Q000379:methods; D004926:Escherichia coli / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008954:Models, Biological; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D014734:Vibrio cholerae / Q000378:metabolism*; D014774:Virulence; D037521:Virulence Factors / Q000378:metabolism
chemical_list: D000992:Antitoxins; D001426:Bacterial Proteins; D058947:Bacterial Secretion Systems; D011994:Recombinant Proteins; C581031:TsaB protein, Vibrio cholerae; C581030:VgrG-3 protein, Vibrio cholerae; D037521:Virulence Factors