Part:BBa_K2819110

PhtpG1 Burden-Driven Promoter

The promoter, PhtpG1, was carefully chosen because of sensitivity to synthetic construct-induced burden in E. coli; the depletion of finite cellular resources during the expression of synthetic constructs constitutes an unwanted burden, hampering the growth and expected the performance of engineered cells in an unpredictable manner. This distinct characteristic is especially valuable to our system because we were interested in quantifying real-time levels of stress generated by the expression of externally introduced constructs. By quantifying cell stress via fluorescence, recombinant protein production can be optimized by the user simply by reducing cell stress i.e. switching off protein production (in our case, this can be done by turning on blue light). Additionally, according to Ceroni et al. (2018), PhtpG1 displayed the best on/off characteristic out of the 4 promoters that were being investigated (htpG1, htpG2, groSL, and ibpAB). This feature allows the promoter to not only respond rapidly but also to maintain its receptivity in a dynamic cell microenvironment.

This promoter has been characterized in depth by attaching the mRFP gene downstream the promoter to express red fluorescence protein (RFP) in response to its level of activation. Please refer to page: https://parts.igem.org/Part:BBa_K2819118 to read more about how this promoter can be useful.

For more information about the burden-driven feedback mechanism, please visit http://2018.igem.org/Team:NUS_Singapore-A.

Sequence and Features

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  COMPATIBLE WITH RFC[12]
• 21
  COMPATIBLE WITH RFC[21]
• 23
  COMPATIBLE WITH RFC[23]
• 25
  COMPATIBLE WITH RFC[25]
• 1000
  COMPATIBLE WITH RFC[1000]

Usage and Biology

• Stress externally introduced via a synthetic construct can be quantified via this part. Levels of fluorescence will be dependent on the amount of stress experienced by the cell since transcription will be driven by the stress-induced promoter.
• Basal stress levels (inherent stress levels, in addition to the stress brought about by the PhtpG1-mRFP construct itself) can be measured.
• Characterization was done in DH5α and BL21 Star (DE3). Ceroni et al. (2018) have also successfully tested the PhtpG1 promoter in MG1655 and DH10B.
• To note: Plasmid backbone part that is inserted should not have the same antibiotic resistance as the bacteria it is transformed into.