Composite

Part:BBa_K3733032

Designed by: Zhenhao Han   Group: iGEM21_HZAU-China   (2021-10-01)


The thiosulfate sensing system under the control of J23103

This part could sense different concentrations of thiosulfate and reflects this difference in fluorescence intensity. Its functionality depends on a two-component system ThsSR, which each constitute a sensor histidine kinase and a response regulator. The ThsS is sensor histidine kinase, which can phosphorylate ThsR in response to thiosulfate. And then the phosphorylated ThsR will binding the site and activate the transcription of PphsA promoter. In this system, we use J23103 to control the expression of ThsS and ThsR, which in turn controls the differentiation of the system to different thiosulfate concentrations.

The function of BBa_K3733032 is confirmed by iGEM 2021 HZAU-China. See this page:https://parts.igem.org/Part:BBa_K3733032:Experience


Sequence and Features


Assembly Compatibility:
  • 10
    COMPATIBLE WITH RFC[10]
  • 12
    INCOMPATIBLE WITH RFC[12]
    Illegal NheI site found at 7
    Illegal NheI site found at 30
    Illegal NheI site found at 1151
    Illegal NheI site found at 1867
  • 21
    INCOMPATIBLE WITH RFC[21]
    Illegal BamHI site found at 550
    Illegal BamHI site found at 598
  • 23
    COMPATIBLE WITH RFC[23]
  • 25
    INCOMPATIBLE WITH RFC[25]
    Illegal AgeI site found at 3065
    Illegal AgeI site found at 3188
  • 1000
    INCOMPATIBLE WITH RFC[1000]
    Illegal SapI site found at 1083
    Illegal SapI.rc site found at 1909


Bacterial thiosulfate sensors (by IGEM23_WHU-China)

Thiosulfate (S2O32-) is a promising biomarker for gut inflammation. Bacterial sensors based on ThsS/R, two-component systems, can be used to diagnose colonic inflammation (colitis) through flow cytometry analysis of colon and fecal samples by responding to thiosulfate.

In a previous study, the sensitivity and specificity of thiosulfate sensors were measured.

Figure 1:Characterization of the thiosulfate sensor ThsSR. (Kristina N-M Daeffler et al. 2017)

In another literature, the ThsS/R-mediated expression of sfGFP was optimized in response to thiosulfate at transcription to increase the induction ratio and enhance the output intensity.

Figure 2:Fluorescence output of each gene circuit. (Zhen-Ping Zou et al. 2023)

It tested the sensitivity of the biosensor to thiosulfate and the specificity by using a panel of metabolites in the gut. The result showed that the biosensor system on pWT-CS2R4 produced a detectable and especially specific signal for a minimal thiosulfate concentration (as low as 0.016 mM).

Figure 3:Thiosulfate dose response of the optimized strain E-sfGFP and EcN. (Zhen-Ping Zou et al. 2023)

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