Part:BBa_K1960050

Low-level expression of LuxR and the lux pR promoter

BBa_A340620 with constant promoter. This part is based on the quorum sensing system of Gram-negative bacterium

Usage and Biology

Research shows that quorum sensing plays an important role in the communication between bacteria. Quorum-sensing bacteria can express and release some small chemical signal molecules called autoinducers. The concentration of the autoinducers increases as a function of cell density. The bacteria can detect a minimal threshold stimulatory concentration of autoinducers, then it will lead to the relevant gene expression. In this case, we designed our sensor based on it.

One quorum sensing system in Gram-negative bacteria is LuxI-LuxR type. LuxI is the autoinducer synthase to produce the acyl-homoserine lactone (AHL) autoinducer, and LuxR is a protein which can bind AHL autoinducer and then activate transcription .In our sensor, the right hand lux promoter (pLuxR) can be activated by LuxR-AHL component

Figure. The diagram of the mechanism that the AHL is sensed by the Lux system sensor part.

Our sensor consists of a promoter BBa_J23106 and LuxR gene with Lux pR BBa_A340620. The BBa_J23106 is a promoter that is on in strains without any inducer, so LuxR gene can express constantly. The concentration of the AHL up to the threshold, the autoinducer AHL binds LuxR. Then the promoter lux pR will be activated, the responder starts to express.

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
  
• 21
  COMPATIBLE WITH RFC[21]
• 23
  COMPATIBLE WITH RFC[23]
• 25
  COMPATIBLE WITH RFC[25]
• 1000
  INCOMPATIBLE WITH RFC[1000]

  Illegal BsaI.rc site found at 985