Part:BBa_K2507000

ThsS

Background

ThsS (BBa_K2507000) and ThsR (BBa_K2507001), both codon-optimized for E. coli, are two basic parts which belong to the two-component system from the marine bacterium Shewanella halifaxensis. ThsS is the membrane-bound sensor kinase (SK) which can sense thiosulfate outside the cell, and ThsR is the DNA-binding response regulator(RR).

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  INCOMPATIBLE WITH RFC[12]

  Illegal NheI site found at 1078
  
• 21
  INCOMPATIBLE WITH RFC[21]

  Illegal BamHI site found at 477
  Illegal BamHI site found at 525
  
• 23
  COMPATIBLE WITH RFC[23]
• 25
  COMPATIBLE WITH RFC[25]
• 1000
  INCOMPATIBLE WITH RFC[1000]

  Illegal SapI site found at 1010
  

Reference

Daeffler, K. N., Galley, J. D., Sheth, R. U., Ortiz‐Velez, L. C., Bibb, C. O., & Shroyer, N. F., et al. (2017). Engineering bacterial thiosulfate and tetrathionate sensors for detecting gut inflammation. Molecular Systems Biology, 13(4), 923.

Jackson MR, Melideo SL, Jorns MS (2012) Human sulfide: quinone oxidoreductase catalyzes the first step in hydrogen sulfide metabolism and produces a sulfane sulfur metabolite. Biochemistry 51: 6804 – 6815

Levitt MD, Furne J, Springfield J, Suarez F, DeMaster E (1999) Detoxification of hydrogen sulfide and methanethiol in the cecal mucosa. J Clin Invest 104: 1107 – 1114

Schmidl SR, Sheth RU, Wu A, Tabor JJ (2014) Refactoring and optimization of light-switchable Escherichia coli two-component systems. ACS Synth Biol 3: 820 – 831

Vitvitsky V, Yadav PK, Kurthen A, Banerjee R (2015) Sulfide oxidation by a noncanonical pathway in red blood cells generates thiosulfate and polysulfides. J Biol Chem 290: 8310 – 8320

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)

Figure 4:Selectivity of ThsS/R to thiosulfate over other terminal electron acceptors. (Zhen-Ping Zou et al. 2023)

Reference

1. Daeffler KN, Galley JD, Sheth RU, Ortiz-Velez LC, Bibb CO, Shroyer NF, Britton RA, Tabor JJ. Engineering bacterial thiosulfate and tetrathionate sensors for detecting gut inflammation. Mol Syst Biol. 2017 Apr 3;13(4):923.
2. Zou ZP, Du Y, Fang TT, Zhou Y, Ye BC. Biomarker-responsive engineered probiotic diagnoses, records, and ameliorates inflammatory bowel disease in mice. Cell Host Microbe. 2023 Feb 8;31(2):199-212.e5.