Lldr-T7-lldPRD operon promoter-GFP
The aim of this part is using llDPRD promoter to activate downstream GFP reporter gene expression under different lactic acid concentration inductions and this operon is repressed without lactic acid induction. Briefly, LLdR repression protein specifically binds to llDPRD promoter and impedes downstream gene expression, while lactic acid enables to antagonize and replace LLdR protein to activate llDPRD promoter (Figure 1). In order to improve the GFP expression, we integrated a strong promoter, T7, into the upstream of lldPRD region.
This part is constructed based on the part lldRO1-plldR-lldRO2 (BBa_k82000). lldRO1-plldR-lldRO2 part is a lactic acid regulated promoter that is open to gene transcription in the presence of lactic acid. Comparing with the T7-lldPRD operon promoter-GFP part, the improvement of this part is that the LLDR is added to part and placed under the control of two promoters respectively to form a double expression regulatory system. This comparison with the two plasmids working together is more convenient for testing the success of the system.
Improve the Characterization of BBa_k82000
We can easily find that the Lldr-T7-lldPRD operon promoter-GFP part are in a higher level of expression comparing to the lldPRD operon promoter-GFP when the lactate concentration is lower than nearly 1.5 mM. Considering that the lactate concentration in yogurt is generally no more than 1 mM, the conclusion can give that the T7 promoter can enhance the signal intensity for our experiments (Figure 2).
Figure 1:Lldr-T7-lldPRD operon promoter-GFP
Figure 2:lldPRD operon promoter-GFP vs Lldr-T7-lldPRD operon promoter-GFP
To see more details about the construction and result, click the hyperlink below: lldPRD operon promoter + RBS from E. coli ( lldRO1-plldR-lldRO2 )：BBa_k82000(http://parts.igem.org/Part:BBa_K822000)
Sequence and Features
- 10COMPATIBLE WITH RFC
- 12Illegal NheI site found at 2390
- 21Illegal BglII site found at 2555
Illegal XhoI site found at 4356
Illegal XhoI site found at 5248
- 23COMPATIBLE WITH RFC
- 25Illegal AgeI site found at 567
Illegal AgeI site found at 1608
- 1000Illegal BsaI site found at 1792
Illegal BsaI.rc site found at 5714
Illegal BsaI.rc site found at 6373
Illegal SapI.rc site found at 1236