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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.

SUBMITTER: Brooks TM

PROVIDER: S-EPMC3597803 | biostudies-literature | 2013 Mar

REPOSITORIES: biostudies-literature

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Lytic activity of the Vibrio cholerae type VI secretion toxin VgrG-3 is inhibited by the antitoxin TsaB.

Brooks Teresa M TM Unterweger Daniel D Bachmann Verena V Kostiuk Benjamin B Pukatzki Stefan S

The Journal of biological chemistry 20130122 11

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 ...[more]

PMID: 23341465

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