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Keyword - Toxin-antitoxin system (KW-1277)


Bacterial, archaeal or viral protein belonging to a toxin-antitoxin (TA) system. Toxin protein expression is poisonous to the cell and is counteracted by its co-expressed, short-lived "antidote" antitoxin. Antitoxins can be protein (type II, IV, V, VI) or RNA (type I, III) and act directly or indirectly on the toxin protein or transcript. Genes for the 2 components are closely linked; in many type II TA systems the toxin-antitoxin complex regulates transcription of its operon. Toxins belong to recognizable protein families, antitoxins usually do not. Orphan toxin genes are occasionally found in complete genomes.


  • Toxin-antitoxin module


Biological process


Toxin-antitoxin systemBiological process