Marimon Garrido, OriolTeixeira, Joao M. C.Cordeiro, Tiago N.Soo, Valerie W. C.Wood, Thammajun L.Mayzel, MaximAmata, IreneGracía, JesúsMorera, AinaraGay i Marín, MarinaVilaseca Casas, MartaOrekhov, Vladislav YuWood, Thomas K.Pons Vallès, Miquel2017-02-202017-02-202016-12-082041-1723https://hdl.handle.net/2445/107125The 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.10 p.application/pdfengcc-by (c) Marimon Garrido, Oriol et al., 2016http://creativecommons.org/licenses/by/3.0/esEspectrometria de massesEspectroscòpia de ressonància magnètica nuclearEscheríchia coliMass spectrometryNuclear magnetic resonance spectroscopyEscherichia coliinfo:eu-repo/semantics/article6678292017-02-20info:eu-repo/semantics/openAccess27929062