Difference between revisions of "Part:BBa K5152006"

Revision as of 04:55, 26 September 2024

MerR-pCadA cadmium sensing chromoprotein reporter device

This part was used to create a cadmium-sensing biosensor for our project, inspired by iGEM 2015 Team SCUT (BBa_K1724000).

The pCadA promoter is cadmium-activated and normally repressed by MerR, which binds mercury. In our design, we used a modified MerR (BBa_K1724001) that binds to cadmium, making the system sensitive to cadmium.

We co-expressed the modified MerR under a medium-strength promoter to enhance sensitivity. The cell strain we used was TOP10 E. coli.

Our goal is to develop biosensors for heavy metals that don't require special techniques or expensive equipment. Therefore, we used chromoproteins for their visible colors. This biosensor uses the amilCP chromoprotein, which turns cells blue in the presence of cadmium.

Our project also examined several chromoproteins, including amilCP, cjBlue, tsPurple, eforRed, and dTomato. For more details, please refer to our wiki page.

Usage and Biology

Cadmium Detection Functional Assay

Our biosensor design effectively detected cadmium. After adding 200 µM cadmium (II) chloride to the culture, the cells showed visible blue coloration in the pellet after 12 hours. However, we consistently observed that extending the incubation time caused the negative control to also turn blue, indicating leaky expression. Therefore, it's important to carefully choose specific timing and conditions to avoid false positives.

Sequence and Features