Part:BBa_K4645015

The pH-sensitive circuit

The pH-sensitive circuit can detect pH changes when engineered bacteria enter a cat's digestive tract and take effect, expressing CI protein to inhibit the expression of antitoxin protein MntA. At the same time, it expresses the two-component system RstAB. RstB can sense the decrease in pH to phosphorylate RstA, and RstA can increase the activity of the acid-induced promoter Pasr, thus quickly increasing the expression of CI protein. The toxin protein HepT and antitoxin protein MntA form a toxin-antitoxin pathway, where the expression of MntA protein is inhibited by CI protein.The circuit design is shown in the diagram below.

Figure 1. Acid-sensitive suicide and Toxin-antitoxin system.