Creation of a promoter library

Figure 1. Theoretical sensitivity shift of the P_LuxR promoter to sense and distinguish different AHL concentrations.

The wild-type P_LuxR promoter ([http://parts.igem.org/Part:BBa_R0062 BBa_R0062]) in the Plac-LuxR-pLuxR [http://parts.igem.org/Part:BBa_J09855 BBa_J09855] construct gets activated in presence of AHL. In our project we need different sensitive promoters to distinguish between different levels of the AHL concentrations according to the different number of surrounding mines. Therefore we need to shift the dose-response curve of the initial [http://parts.igem.org/Part:BBa_R0062 BBa_R0062] promoter. We decided to do site directed saturation mutagenesis (see below) to achieve a sensitivity shift and create a promoter library. For more details please see the experimental results page of processing.

Site directed saturation mutagenesis PCR of the BBa_R0062 P_LuxR

Figure 2: Promoter mutation sites The wild type promoter from the biobrick [http://parts.igem.org/Part:BBa_R0062 BBa_R0062] was mutated using site directed saturation mutagenesis. The library shows the targeted sites for site directed saturation mutagenesis. The sequences for the library, the [http://parts.igem.org/Part:BBa_R0062 BBa_R0062], the [http://parts.igem.org/Part:BBa_K1216007 BBa_K1216007] and the wild type luxR promoter from literature Antunes et. al., 2007. are given.

The [http://parts.igem.org/Part:BBa_R0062 BBa_R0062] promoter contains a binding site for a LuxR-AHL complex as well as an RNA polymerase binding site. Our system needs different sensitive promoters to detect different concentrations of AHL according to the number of surrounding mines. Therefor we need to engineer this promoter in order to shift the dose response curve (which we first had to characterize). Finally after some research we decided to do site directed saturation mutagenesis in the palindromic LuxR binding sites of the luxbox according to the results taken from literature Antunes et. al., 2007. (see Figure 2).

About the promoter library:
First of all we isolated the mutated P_LuxR [http://parts.igem.org/Part:BBa_K1216007 BBa_K1216007] which shows an important shift. We than back-mutated this mutant using oligomers and finally isolated 7 new additional promoters. (We did not have time to submit them to the registry). Please see the results page to see our library

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