Part:BBa_K2257006
hydrogen sulfide sensor sequence
SQR is a NAD(P)/FAD-dependent oxidoreductase, which oxidizes S2- to zero-valent S0. SqrR, encoded by sqrR, is a constitutively expressed suppressor protein of sqr promotor. RFP is the indicator. When there is no H2S in the environment, SqrR combines with the sqr promotor and keeps the expression of both the enzyme and RFP at a low level. While in the case where H2S exists, it will be oxidized by the small amount of expressed enzyme, and the product will interact with SqrR, forming a tri- or tetrasulfide cross-links linking C41 and C107 on the same subunit of SqrR. The change in the structure of SqrR makes it fall off from the sqr promotor and thus the expression of SQR and RFP turns on. The part can be used to detect hydrogen sulfide at a μmol level.
Usage and Biology
As to the hydrogen sulfide sensor, we also designed a whole-cell biocatalytic system, displaying the concentration of hydrogen sulfide by the compound’s influence on specific genes’ expression in modified E.coli. Our idea is inspired from a type of bacterium that can live on sulfide.
A plate sensitive assay measuring S2– tolerance of E. coli cells with constructed probe pathway. All plates were incubated at 37℃ for 18 h before being read. No significant influence appeared to the growth of E. coli at a concentration lower than 10mmol/L.
We analysised the product by dual-enzyme digestion and electrophoresis.
Sequence and Features
- 10COMPATIBLE WITH RFC[10]
- 12COMPATIBLE WITH RFC[12]
- 21INCOMPATIBLE WITH RFC[21]Illegal XhoI site found at 1373
Illegal XhoI site found at 1574
Illegal XhoI site found at 2261
Illegal XhoI site found at 2375
Illegal XhoI site found at 2573 - 23COMPATIBLE WITH RFC[23]
- 25COMPATIBLE WITH RFC[25]
- 1000INCOMPATIBLE WITH RFC[1000]Illegal BsaI.rc site found at 1304
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