Part:BBa_K2097000
CpxR binding site attached to a yellow-green color protein (YGCP) acts as a neutral pH indicator.
- 10COMPATIBLE WITH RFC[10]
- 12COMPATIBLE WITH RFC[12]
- 21COMPATIBLE WITH RFC[21]
- 23COMPATIBLE WITH RFC[23]
- 25COMPATIBLE WITH RFC[25]
- 1000COMPATIBLE WITH RFC[1000]
Usage and Biology
CpxA-CpxR is a two-component mechanism that is activated at pH 7.4 and repressed at pH 6.0. CpxA is an intermembrane protein that autophosphorylates at a certain external pH, CpxR (a kinase) then gets phosphorylated by CpxA and acts as a transcription factor for the downstream gene, YGCP in this case. This system originally is a transcription factor for the virF gene, but virF was replaced with a reporter. The original sequence was found in Shigella sonnei, but E. coli has a homolog of these proteins[1] [2]. Only the appropriate BioBrick prefix/suffix and CpxR binding site were required to design the part. Used BBa_K2097002 as the control series.
[1] Nakayama, S.-I., and Watanabe, H. (1998) Identification of cpxR as a Positive Regulator Essential for Expression of the Shigella sonnei virF Gene. Journal of Bacteriology 180, 3522–3528
[2]Nakayama, S.-I., and Watanabe, H. (1995) Involvement of cpxA, a Sensor of a Two-Component Regulatory System, in the pH-Dependent Regulation of Expression of Shigella sonnei virF Gene. Journal of Bacteriology 177, 5062–5069
Experimental Design
Figure 1.The blue data points represent fluorescent readings with the control series (BBa_K2097002), while the orange data points are the Cpx construct. As one can see, the Cpx construct shows increased fluorescence as the pH increases from 6 to 9.
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