An oxygen-sensitive toxin-antitoxin system.

Marimon O, Teixeira JM, Cordeiro TN, Soo VW, Wood TL, Mayzel M, Amata I, GarcĂ­a J, Morera A, Gay M, Vilaseca M, Orekhov VY, Wood TK, Pons M

Nat Commun 7 (-) 13634 [2016-12-08; online 2016-12-08]

The Hha and TomB proteins from Escherichia coli form an oxygen-dependent toxin-antitoxin (TA) system. Here we show that YmoB, the Yersinia orthologue of TomB, and its single cysteine variant [C117S]YmoB can replace TomB as antitoxins in E. coli. In contrast to other TA systems, [C117S]YmoB transiently interacts with Hha (rather than forming a stable complex) and enhances the spontaneous oxidation of the Hha conserved cysteine residue to a -SOxH-containing species (sulfenic, sulfinic or sulfonic acid), which destabilizes the toxin. The nuclear magnetic resonance structure of [C117S]YmoB and the homology model of TomB show that the two proteins form a four-helix bundle with a conserved buried cysteine connected to the exterior by a channel with a diameter comparable to that of an oxygen molecule. The Hha interaction site is located on the opposite side of the helix bundle.

Swedish NMR Centre (SNC) [Collaborative]

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PubMed 27929062

DOI 10.1038/ncomms13634

Crossref 10.1038/ncomms13634

ncomms13634

pmc PMC5155140