Part:BBa_K4998039

LuxI transcription unit under the PgroE promoter

Usage and Biology

This part is the transcription unit of the quorum sensing LuxI gene. It consists of the promoter PgroE (BBa_K4998026), the native RBS R0 (BBa_K3831018), the LuxI gene sequence (BBa_K4998027), and a B. subtilis terminator (BBa_K780000). This part contains the coding region of an Acyl-Homoserine Lactone (AHL) synthase enzyme. The AHL synthase encoded by LuxI catalyzes the synthesis of 3-oxo-hexanoyl-HSL, an autoinducer that originates from the Vibrio fischeri marine bacterium. This AHL molecule has the ability of permeating cell membranes, due to its small size and hydrophobicity, and regulates the Vibrio fischeri’s expression of luminescence proteins, depending on whether it survives in a free-living state, thus having small cell densities (no luminescence), or in a host-associated state, when cell population rises (luminescence). [1] The AHL functions as a signaling molecule, enabling the communication between neighboring cells, by creating a quorum sensing system. The more the cells in a colony, the more AHL is produced, leading to the activation of the QS system and the luminescence protein production. [2]

LuxI’s AHL synthase is a 193 amino acid peptide that uses the protein carrier of 3-oxo-hexanoyl acyl as a substrate to synthesize the 3-oxo-hexanoyl-HSL from S-adenosylmethionine and 3-oxo-hexanoyl co-enzyme a. This part encodes the AHL-synthase protein sequence. [1]

In our project, we utilize the LuxI part, along with BBa_K4998022 (LuxR CDS) to develop a quorum sensing system between the Bacillus subtilis WB800N strain and the Nostoc oryzae TAU-MAC 2710 cyanobacterial strain. The QS’s aim is the development of a kill switch mechanism for the cyanobacterial strain, so as Nostoc will come to death at the same time as the Bacillus subtilis.

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  COMPATIBLE WITH RFC[12]
• 21
  INCOMPATIBLE WITH RFC[21]

  Illegal XhoI site found at 26
  
• 23
  COMPATIBLE WITH RFC[23]
• 25
  COMPATIBLE WITH RFC[25]
• 1000
  COMPATIBLE WITH RFC[1000]

References

[1] Fuqua, W. C., Winans, S. C., & Greenberg, E. P. (1994). Quorum sensing in bacteria: The luxr-luxi family of cell density-responsive transcriptional regulators. Journal of Bacteriology, 176(2), 269–275. https://doi.org/10.1128/jb.176.2.269-275.1994

[2] Kokarakis, E. J., Rillema, R., Ducat, D. C., & Sakkos, J. K. (2022). Developing cyanobacterial quorum sensing toolkits: Toward interspecies coordination in mixed autotroph/heterotroph communities. ACS Synthetic Biology, 12(1), 265–276. https://doi.org/10.1021/acssynbio.2c00527