FIG 4.

Graphical representations of antitoxin-toxin interactions and their classification in the different types of TA systems in clinical pathogens. (A) Type I. There is an interaction between mRNAs that blocks toxin protein formation. (B) Type II. The antitoxin protein forms a complex with the toxin protein, inhibiting its function. (C) Type III. The antitoxin mRNA generates a complex with the toxin protein, inhibiting its function. (D) Type IV. The antitoxin protein competes with the toxin for its substrates. (E) Type V. The toxin mRNA is degraded by an RNase encoded by the antitoxin gene. (F) Type VI. A TA complex is formed by the union of toxin and antitoxin proteins, producing decomposition of the toxin by a cellular protease. (Adapted from reference 16.)