An oxygen-sensitive toxin-antitoxin system.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 27929062.
- Also identified by DOI 10.1038/ncomms13634 and PMC identifier 5155140.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
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 -SO<sub>x</sub>H-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.
Medical subject headings
- DNA-Binding Proteins
- Escherichia coli Proteins
- Toxin-Antitoxin Systems