Difference between revisions of "Part:BBa K3161003"

Latest revision as of 03:32, 22 October 2019

Pc-RBS-PbrR-W

PbrR protein expressed under the control of weak Anderson promoter J23117

Usage and Biology

Aim of experiment

PbrR is a lead-binding protein in the form of dimer. In the presence of lead ions, Pb2+ binds to the PbrR protein dimer, resulting in a conformational change that causes lead sensitive promoters to begin transcription. In order to design biosensor that can detect different concentration of lead threshold, we designed a series of parts expressing PbrR protein under the control of different strength constitutive promoter, including strong promoter J23100, medium promoter J23106 and weak promoter J23117.

Results

PbrR-W (K3161003) was expressed under the control of weak Anderson promoter J23117. We measured the protein expression of three kinds of PbrR, and the results were as follows As can be seen from figure 1, PbrR protein expressed under different strengths of constitutive promoters J23100(S), J23106 (M) and J23117 (W). The order of expression intensity is S>M>W. This also explains why biosensors constructed in S, M and W have different tolerance to lead. As shown in figure 2, biosensors containing PbrR-S were more resistant to Pb2+, while biosensors composed of PbrR-M (K3161002) or PbrR-W(K3161003) were less resistant to high concentrations of lead (5ppm and 10ppm), indicating that PbrR expression played a role in the adsorption of lead by cells.

Fig1. PbrR protein expression under different strength of Anderson promoters in SDS-PAGE. S, strong Anderson promoter J23100, M, medium promoter, J23106, W, weak promoter J23117.

Fig2. Effect of PbrR protein expression under the control of different strength of promoters on bacteria resistance to lead. S, strong Anderson promoter J23100, M, medium promoter, J23106, W, weak promoter J23117.

Sequence and Features