HKU’s iGEM team aims to introduce
an acyl homoerine lactone (AHL)-degrading genetic system into the non-biolfilm-forming
and non-virulent BL21 Escherichia coli strain. PvdQ, an enzyme naturally
produced by Pseudomonas aeruginosa, is an acylase that functions to
degrade long chain AHLs that bacteria like Pseudomonas putida or
aeruginosa itself utilize for biofilm formation. Biofilms are population
density-dependent structures formed by quorum sensing bacteria that
produce and secrete auto-inducers, which signal selective gene
transcription. These signaling molecules, namely the AHLs, are
responsible for most bacterial pathogenicity including the opportunistic
respiratory infections caused by P.aeuroginosa in immunocompromised
patients.
As a step towards combating these infections, E.coli can be effectively
used as a protein factory to maximize pvdQ yield in vitro or ex vivo.
Our most preliminary biobrick is a constitutive promoter that drives
baseline, exponential expression of pvdQ. This genetic pathway is
advantageous because the pvdQ gene is constitutively transcribed
regardless of environmental and endogenous factors.