From 2014.igem.org

Biology - Classic & RNAseq-based sensors

Phenol biosensor :

PCBs biosensor :

Biosensor parts

bphR2 gene, from Pseudomonas alcaligenes KF707, encodes for a prokaryotic regulatory protein. This gene is located upstream from the bph genes which are implied in the degradation of PCBs and regulates them negatively. bphR2 protein can detect PCBs when it diffuses into the cell and activate degradation genes.

The construction is composed by a constitutive promoter (BBa_J23114), a RBS (BBa_B0034), bphR2 gene (BBa_K1413021), which has been mutated because of a pstI site in its sequence, bphR1 promoter region (BBa_K1155001), received from Saclay’s team, RFP (BBa_E1010) and a terminator (BBa_B0015)

How function our biosensor ?

In absence of PCBs :
bphR2 (BBa_K1413021) is bound to bphR1 promoter (BBa_K1155001). Transcription of RFP isn't possible.

In presence of PCBs :
When compound diffuses into the cell, it binds to bphr2 protein. This protein undergoes a conformational change and releases from the promoter that its allows the transcription of RFP.