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Publication Abstract from PubMed

Toxin-antitoxin (TA) systems are a large family of genes implicated in the regulation of bacterial growth and its arrest in response to attacks. These systems encode nonsecreted toxins and antitoxins that specifically pair, even when present in several paralogous copies per genome. Salmonella enterica serovar Typhimurium contains three paralogous TacAT systems that block bacterial translation. We determined the crystal structures of the three TacAT complexes to understand the structural basis of specific TA neutralization and the evolution of such specific pairing. In the present study, we show that alteration of a discrete structural add-on element on the toxin drives specific recognition by their cognate antitoxin underpinning insulation of the three pairs. Similar to other TA families, the region supporting TA-specific pairing is key to neutralization. Our work reveals that additional TA interfaces beside the main neutralization interface increase the safe space for evolution of pairing specificity.

Auxiliary interfaces support the evolution of specific toxin-antitoxin pairing.,Grabe GJ, Giorgio RT, Hall AMJ, Morgan RML, Dubois L, Sisley TA, Rycroft JA, Hare SA, Helaine S Nat Chem Biol. 2021 Dec;17(12):1296-1304. doi: 10.1038/s41589-021-00862-y. Epub , 2021 Sep 23. PMID:34556858^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.