IGEM:IMPERIAL/2006/project/Oscillator/project browser/Predator Construct/Design

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Super Parts Molecular Prey-Predator Oscillator
Actual Part
Sub Parts Test Sensing Predator Construct Test Killing Predator Construct


Registry

  • 2 parts have been designed to fullfil the specifications:
  • a monocystronic: <bbpart>BBa_J37035</bbpart>
Image:J37035 parts pic.PNG
  • a polycystronic: <bbpart>BBa_J37036</bbpart>
Image:J37036 parts pic.PNG

Design choices

  • We need to fulfill all the properties listed in the specifications.
  • Based on the Quorum-sensing/quenching due to biochemical properties needed and BioBricks availability.
  • Following the design of the Prey-construct, the prey molecule is an homoserine-lactone (AHL).
  • Due to the biochemical constrains, the predator has to be decoupled into 3 modules:
    • Sensing module driven by the dimer formed between AHL and LuxR and its affinity to the pLux promoter.
    • Killing module driven by the use of the lactonase aiiA.
    • Natural death of the predator molecule.


INPUTS biological component comments
Prey molecule AHL Homoserine lactone synthesized by the LuxI gene <bbpart>BBa_C0061</bbpart>
OUTPUTS biological component comments
Prey molecule AHL Homoserine lactone synthesized by the LuxI gene <bbpart>BBa_C0061</bbpart>
Predator molecules LuxR <bbpart>BBa_C0062</bbpart> In complex with HSL, LuxR binds to the pLux promoter, activating transcription
aiiA lactonase <bbpart>BBa_C0160</bbpart> Capable in degrading AHL
FUNCTIONS biological component comments
Prey Sensing pLux promoter <bbpart>BBa_R0062</bbpart> The pLux promoter allows us to get the growth of the predator to be function of the population of prey-molecules and predator-molecules.
Prey Killing Enzymatic reaction Enzymatic reaction from aiiA on AHL .
Predator Death Growth dilution Bacterials will be washed out from the chemostat, so will be the LuxR and aiiA inside the bacterials, and this should be much more dominant than LuxR and aiiA's natural degrdation rate

Open issues

  • Testing should be done to distinguish between the monocystronic and polycystronic construct (maybe their transfer functions are different)
  • If the degradation rates of LuxR and aiiA are different, it will introduce an asymmetry in the system.
  • The aiiA BioBrick in the Registry has never been properly tested and validated.

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