(I) Statistical mechanics provides a way describe the system in terms of the number of repressors and repressor binding sites, their binding affinity and the position of the repressor binding on the promoter [1,2].
(II) In contrast to Michaelis-Menten kinetics, statistical mechanics offers more freedom studying the behavior of differently designed promoters.Michaelis-Menten requires the dissociation constants of the repressor proteins to be experimentally determined [1,2].
Based on the results of the model the experimentalists ordered oligonucleotides and assembled six promoters. Building two Kill-switches in parallel the chance of constructing a stable system increases. The assumption that the system is optimized and stable has been incorporated in the model quantifying stability .