Part:BBa_K4619010

PobR-Threshold Guard Switch

The gene pobR creates a transcriptional activator that attaches to the pobR operator on the dsDNA before combining with 4-HBA. Once 4-HBA is introduced to the solution, PobR binds with it and triggers the transcription of the dual pobA/R promoter on the side of pobA. One of the advantages of this protein is its sensitivity and low leakage properties. Even tiny amounts of 4-HBA, at the micromolar level, can trigger transcription. This characteristic is crucial in creating a high-quality digitizer with a sharp response between two stable states(Calles et al., 2019). Additionally, research indicates that most analogs of 4-HBA, such as p-aminobenzoate, can impede the activation of PobR, ensuring precise detection of 4-HBA. Moreover, the combination of the non-activated PobR and pobR operator will inhibit the transcription of pobR when there is no 4-HBA stimulus, reducing the pressure on our bacteria. Given PobR's excellent properties, we create a chimeric switch by combining it with a portion of the original threshold guard switch.