Part:BBa_K4390098
merR controlled Squash biosensor
The Edinburgh-UHAS_Ghana team for 2022 designed a construct to detect mercury in contaminated water. This construct is composed of a fluorescent RNA aptamer Squash flanked by the F30 tRNA scaffolds (BBa_K4390096) which under a strong T7 RNA promoter (BBa_I712074), downstream of the promotor there is the mercury promotor which acts as the binding site for the merR repressor (BBa_K346002) as to allow transcriptional repression of the T7 promotor. This construct is designed to be cell-free and only requires transcription of the RNA aptamer to produce fluorescence. It should be noted that T7 RNA polymerase, chemical energy (ATP), NTPs and DFHBI or DFHO are also required in the cell-free reaction so that fluorescence is observed.
Usage and Biology
This biosensor should be used with a cell-free lysate which contains the merR repressor, T7 RNA polymerase, chemical energy (ATP), NTPs and DFHBI or DFHO to induce fluorescence in the presence of mercury ions. The merR repressor will bind to the merR binding site on the mercury promoter when mercury ions are not present in the reaction. This causes transcriptional repression of the RNA aptamer as the T7 polymerase is physically occluded from reading the linear construct. When mercury ions are present in the reaction the pbrR repressor will then bind to the mercury ions and it will allow the transcription of the RNA aptamer, this aptamer can then bind to the DFHBI or DFHO which will induce fluorescence.
Sequence and Features
- 10COMPATIBLE WITH RFC[10]
- 12COMPATIBLE WITH RFC[12]
- 21COMPATIBLE WITH RFC[21]
- 23COMPATIBLE WITH RFC[23]
- 25COMPATIBLE WITH RFC[25]
- 1000COMPATIBLE WITH RFC[1000]
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