Part:BBa_K2507017

J23109-ttrR-PttrB185-BBa_K274003

Usage and Biology

E. coli-codon-optimized TtrS(BBa_K2507002) and TtrR (BBa_K2507003) are two basic parts which are derived from the two-component system of the marine bacterium Shewanella baltica. TtrS is the membrane-bound sensor kinase (SK) which can sense tetrathionate outside the cell, and TtrR is the DNA-binding response regulator (RR). PttrB185-269 (BBa_K2507019) is a minimal TtrR-activated promoter which is activated when TtrR is phosphorylated by TtrS after TtrS senses tetrathionate.

Winter et al. have shown that reactive oxygen species (ROS) produced by the host during inflammation convert thiosulfate into tetrathionate, which this pathogen consumes to establish a beachhead for infection (Winter et al, 2010). Thus, tetrathionate may correlate with pro-inflammatory conditions and can therefore be used as a sensor for intestinal inflammation.

Sequence and Features

Assembly Compatibility:

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

  Illegal NheI site found at 11
  Illegal NheI site found at 34
  Illegal NheI site found at 2062
  
• 21
  COMPATIBLE WITH RFC[21]
• 23
  COMPATIBLE WITH RFC[23]
• 25
  INCOMPATIBLE WITH RFC[25]

  Illegal NgoMIV site found at 4847
  Illegal AgeI site found at 318
  Illegal AgeI site found at 5043
  
• 1000
  INCOMPATIBLE WITH RFC[1000]

  Illegal SapI.rc site found at 6272
  Illegal SapI.rc site found at 6347
  

Characterization

We first validated that this system can function as a tetrathionate sensor and reporter in the laboratory strains Escherichia coli Top10 and E. coli Nissle 1917.

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Figure 1. Schematic diagram of ligand-induced signaling through TtrS/R and plasmid-borne implementation of the sensor components. TtrS/R was tested with BBa_K2507006 integrated into the pSB4K5 backbone and BBa_K2507017 into the pSB1C3 backbone. We submitted all parts to the iGEM registry in pSB1C3.

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.