Part:BBa_K2587024

luxI_luxR_P_lux_E

This part is an assembly of different constructs, which then yield a final plasmid, able to self lyse Escherichia coli cells. It is a construct based on the Quorum sensing system of Vibrio fischeri. With the addition of a lysis gene it will induce cell lysis upon synthesis of the quorum sensing molecule acyl homoserine lactone. Upon synthesis of this by the LuxI gene, it will bind to the regulator LuxR and then to the promoter pLux, which will activate synthesis of the lysis protein E from the bacteriophage phiX174E.

Usage and Biology

• Acyl homoserine lactone synthase : LuxI
• Regulator: LuxR
• Promoter: pLux, inducible by the quorum sensing molecule acyl homoserine lactone bound to LuxR
• Lysis gene: Lysis gene E from bacteriophage phiX174E
• Lysis protein induces host cell lysis by inhibiting host translocase MraY activity, which is necessary for catalysis of lipid I , a factor for cell wall synthesis (Cytolysis) (1)
• This construct is able to modify E.coli´s growth, by slowing it down
• This part contains Type II S restriction sites and can be further used for scarless assembly with other parts

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 829
  Illegal NheI site found at 852
  
• 21
  INCOMPATIBLE WITH RFC[21]

  Illegal BglII site found at 1082
  
• 23
  COMPATIBLE WITH RFC[23]
• 25
  COMPATIBLE WITH RFC[25]
• 1000
  INCOMPATIBLE WITH RFC[1000]

  Illegal BsaI site found at 892
  Illegal BsaI site found at 1681
  Illegal BsaI site found at 1832
  Illegal BsaI.rc site found at 1523
  Illegal BsaI.rc site found at 1790
  

Characterization

Characterisation of promoter by fluorescence measurement of GFP
To check whether the promoter, pLux, is really induced by the binding of the acyl homoserine lactone to the LuxR, a further construct (BBa_K2587027) is created which has the lysis gene E exchanged by a GFP gene. Here the relative fluorescence units are measured in comparison to the wild type E.coli cells.

Results It can clearly be observed, that fluorescence increases upon growth of the cells. Wild type cells, as a negative control, show little or no fluorescence at all.

Figure 1>: Relative fluorescence measurement of lysis construct and E.coli wild type cells (negative control). Exctinction: 485nm; Emission: 520nm.