Fig. 1.

Types of TA system- TA system has been categorized in eight types based on the antitoxin mode of inhibition of toxin. A. In type I, antitoxin RNA binds to toxin mRNA and inhibits toxin mRNA translation. B. In type II, antitoxin interacts with toxin and inhibits toxin activity. C. In type III, antitoxin RNA binds to toxin and inhibits its activity. D. In type IV antitoxin binds to the substrate of toxin and inhibits toxin activity indirectly. E. In type V, antitoxin cleaves toxin mRNA and inhibits its translation. F. In type VI, antitoxin interacts with toxin and act as proteolytic adapter for degradation for toxin. G. In type VII, antitoxin interacts with toxin and inhibits toxin activity via post-translational modification. H. In type VIII, antitoxin RNA inhibits the transcription of toxin or promotes toxin RNA degradation. Toxins of all types of TA system are either bacteriostatic or bactericidal in nature.