Coding

Part:BBa_K1017301

Designed by: Wen-Hui Cheng   Group: iGEM13_NCTU_Formosa   (2013-09-12)
Revision as of 15:28, 29 September 2013 by AggieTsai (Talk | contribs) (Quantitative data showing the Part or Device function)

Cph8(cph1-envZ)


The red light sensor (Cph8) is a fusion protein which is consisted of a phytochrome Cph1 and a histidine kinase domain, Envz-OmpR, that includes a response regulator.Cph1 is the first member of the plant photoreceptor family that has been identified in bacteria. The functional expression of a phytochrome domain(Cph1) in E. coli requires the biosynthesis of the respective bilin chromophore PCB. EnvZ-OmpR, a dimeric osmosensor, is a multidomain transmembrane protein and one of the best characterized two-component histidine kinases from E.coli.

With the biosynthesis of PCB, Cph1 serve as a red-light absorbing chromophore that is inactivated under red light and activated without red light. Upon changes of extracellular osmolarity, EnvZ specifically phosphorylates its cognate response regulator OmpR, which, in turn, regulates the PompC.

Mechnism

Cph8 can serve as a photoreceptor that regulates gene expression through PompC. Without red light, Cph1 is activated and it enables EnvZ-OmpR to autophosphorylate which in turn activates PompC. Under the exposure of red light, however, Cph1 is deactivated, inhibiting the autophosphorylation, thus turning off gene expression. Take the image beneath as an example, in the dark, the phosphorylated OmpR will turn on PompC to produce lacI protein.

Nctu formosa cph8mechnism.jpg

Quantitative data showing the Part or Device function

To test whether red light and Cph8 can regulate Pred or not, we measured the florescence expression of E. coli that were exposed to red light under 37 °C. The figure shows that red light can in fact activate Pred. Colony 5 displays a high normalized expression under red light, suggesting that the biobrick was successfully activated by red light. In other words, our Cph8 can work. On the other hand, colony 3 might be mutated, as it shows only little expression.

600px-NCTU result Activation Efficiency of light regulated system.png

Sequence and Features


Barcodes are discontinued, but one was appended to the sequence of this part. Composite parts using this part will include the barcode. More ...

Assembly Compatibility:
  • 10
    COMPATIBLE WITH RFC[10]
  • 12
    COMPATIBLE WITH RFC[12]
  • 21
    INCOMPATIBLE WITH RFC[21]
    Illegal XhoI site found at 364
  • 23
    COMPATIBLE WITH RFC[23]
  • 25
    COMPATIBLE WITH RFC[25]
  • 1000
    COMPATIBLE WITH RFC[1000]


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