Amino acid residues crucial for specificity of toxin-antitoxin interactions in the homologous Axe-Txe and YefM-YoeB complexes

作者：Polom Dorota; Boss Lidia; Wegrzyn Grzegorz; Hayes Finbarr; Kedzierska Barbara^*

来源：FEBS Journal, 2013, 280(22): 5906-5918.

DOI：10.1111/febs.12517

• axe-txe
• protein interaction specificity
• toxin-antitoxin
• yefM-yoeB

Toxin-antitoxin complexes are ubiquitous in bacteria. The specificity of interactions between toxins and antitoxins from homologous but non-interacting systems was investigated. Based on molecular modeling, selected amino acid residues were changed to assess which positions were crucial in the specificity of toxin-antitoxin interaction in the related Axe-Txe and YefM-YoeB complexes. No cross-interactions between wild-type proteins were detected. However, a single amino acid substitution that converts a Txe-specific residue to a YoeB-specific residue reduced, but did not abolish, Txe interaction with the Axe antitoxin. Interestingly, this alteration (Txe-Asp83Tyr) promoted functional interactions between Txe and the YefM antitoxin. The interactions between Txe-Asp83Tyr and YefM were sufficiently strong to abolish Txe toxicity and to allow effective corepression by YefM-Txe-Asp83Tyr of the promoter from which yefM-yoeB is expressed. We conclude that Asp83 in Txe is crucial for the specificity of toxin-antitoxin interactions in the Axe-Txe complex and that swapping this residue for the equivalent residue in YoeB relaxes the specificity of the toxin-antitoxin interaction.

• 出版日期2013-11