One cannot rule them all: Are bacterial toxins-antitoxins druggable?

Chan, Wai Ting; Balsa, Dolors; Espinosa, Manuel

TAs are usually composed of two genes: the toxin gene encodes a toxin protein that has toxic effect to the cells, whereas the antitoxin can be either RNA or protein, which counteracts the toxicity of its cognate toxin. Depending on the mode of the antitoxin to neutralize the toxin, TAs have been grouped into five types so far: (i) type I, the antitoxin antisense RNA prevents translation of the toxin protein by binding to its complementary toxin mRNA; (ii) type II, the antitoxin protein binds to the toxin protein through protein-protein interactions (PPI); (iii) type III, the antitoxin mRNA interacts directly to the toxin protein; (iv) type IV, the antitoxin protein interferes the binding of the toxin protein to the cell target, and (v) type V, the antitoxin protein cleaves specifically its cognate toxin mRNA (Hayes and Van Melderen 2011; Masuda et al., 2012; Wang et al., 2012) .