Mathematical Modeling: Bridging the Gap between Concept and Realization in Synthetic Biology

Figure 8

The six possible binding states in the repressor-activator model in Guido et al. [8]. The rectangular boxes represent the three available operator sites of engineered O_RO_lac promoter. Unbound sites are depicted with unfilled (white) boxes; filled (pink) boxes depict sites bound by the appropriate protein (lacI to O_lac, cI to O_R1 and O_R2). Of the eight (2³) possible states, two are not feasible. This is because cI binds sequentially to the O_R1 and O_R2 sites so that O_R2 cannot bind unless O_R1 is also bound. The model parameters 𝐾₁₂ through 𝐾₅₆ are the rate constants for the transitions between each possible binding state (adapted from Guido et al. [8]).