To properly tune the quorum sensing to the right bacterial cell density threshold, we had to characterize the influence of the basal expression of luxR on our system.

Given the data we gathered from literature, giving us the binding constants of AHL to luxR, the dimerization constant of this complex, and the binding of this transcription factor complex to the luxR binding site controlling the expression of the operon, we could hope to deduce the amount of luxR present in our bacteria from the dose response of a strain containing part of our quorum sensing circuit. The quorum sensing pathway cannot be complete indeed, as the presence of luxI would trigger a positive feedback loop interfering in the amount of AHL, which we want to tightly control to establish the dose-response curve.