Part:BBa_K4645004

VqmAphage

vqmA gene would translate into protein VqmA_Phage.
Vibrio cholerae uses a quorum-sensing (QS) system composed of the autoinducer 3,5-dimethylpyrazin-2-ol (DPO) and receptor VqmA, which together repress genes for virulence and biofilm formation [1]. VqmA_Vc activates expression of the vqmR gene encoding the small regulatory RNA VqmR. Vibriophage VP882 encodes a VqmA homolog called VqmA_Phage that activates the qtip promoter (P_qtip). It’s worth noting that, VqmA_Phage can activate vqmR expression but VqmA_Vc cannot activate expression of qtip. Promoter selectivity is driven by each VqmA DNA-binding domain and key DNA sequences in the vqmR and qtip promoters are required to maintain specificity. [2]

Usage and Biology

We assembled this part with P_qtip then transfected into E. coli to sensing the density of bacteria and regulate the circuit.

Figure 1. The circuit we assembled.

Characterization

Successful protein expression

We transformed vqmA into BL21(DE3) and cultivated in 37℃, 220 rpm. When the OD₆₀₀ of bacteria reached 0.6, we induced bacteria with 1 mM, 2 mM IPTG, then cultivated for about 12 hours. Here is SDS-PAGE gel figure of VqmA_phage.

Figure 2. SDS-PAGE gel figure of VqmA_phage.

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  COMPATIBLE WITH RFC[12]
• 21
  COMPATIBLE WITH RFC[21]
• 23
  COMPATIBLE WITH RFC[23]
• 25
  INCOMPATIBLE WITH RFC[25]

  Illegal NgoMIV site found at 535
  
• 1000
  COMPATIBLE WITH RFC[1000]

Reference

[1] Silpe JE, Bassler BL. A Host-Produced Quorum-Sensing Autoinducer Controls a Phage Lysis-Lysogeny Decision. Cell. 2019 Jan 10;176(1-2):268-280.e13.
[2] Duddy OP, Huang X, Silpe JE, Bassler BL. Mechanism underlying the DNA-binding preferences of the Vibrio cholerae and vibriophage VP882 VqmA quorum-sensing receptors. PLoS Genet. 2021 Jul 6;17(7):e1009550.