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- Le, Nguyen-Hung, et al.
(author)
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Killing of Gram-negative and Gram-positive bacteria by a bifunctional cell wall-targeting T6SS effector
- 2021
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In: Proceedings of the National Academy of Sciences of the United States of America. - : National Academy of Science. - 0027-8424 .- 1091-6490. ; 118:40
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Journal article (peer-reviewed)abstract
- The type VI secretion system (T6SS) is a powerful tool deployed by Gram-negative bacteria to antagonize neighboring organisms. Here, we report that Acinetobacter baumannii ATCC 17978 (Ab17978) secretes D-lysine (D-Lys), increasing the extracellular pH and enhancing the peptidoglycanase activity of the T6SS effector Tse4. This synergistic effect of D-Lys on Tse4 activity enables Ab17978 to out-compete Gram-negative bacterial competitors, demonstrating that bacteria can modify their microenvironment to increase their fitness during bacterial warfare. Remarkably, this lethal combination also results in T6SS-mediated killing of Gram-positive bacteria. Further characterization revealed that Tse4 is a bifunctional enzyme consisting of both lytic transglycosylase and endopeptidase activities, thus representing a family of modularly organized T6SS peptidoglycan-degrading effectors with an unprecedented impact in antagonistic bacterial interactions.
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