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An oxygen-sensitive toxin-antitoxin system.

ABSTRACT: 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.

SUBMITTER: Marimon O

PROVIDER: S-EPMC5155140 | biostudies-literature | 2016 Dec

REPOSITORIES: biostudies-literature

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An oxygen-sensitive toxin-antitoxin system.

Marimon Oriol O Teixeira João M C JM Cordeiro Tiago N TN Soo Valerie W C VW Wood Thammajun L TL Mayzel Maxim M Amata Irene I García Jesús J Morera Ainara A Gay Marina M Vilaseca Marta M Orekhov Vladislav Yu VY Wood Thomas K TK Pons Miquel M

Nature communications 20161208

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 -SO<sub>x</sub>H-containing species (sulfenic, sulfinic o ...[more]

PMID: 27929062

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