Part:BBa_K861050
FadR, fatty acid sensor from E.coli str. K12
FadR is a transcription regulator, which, when not binds to acyl-CoA can either serve as an activator for fatty acid synthesis gene like FabA, FabB and etc. or a repressor for fatty acid degradation gene like FadA, FadB, FadD and etc. After long chain fatty acid is converted into fatty acyl- CoA by FadD, it can bind to FadR. This binding will alter the conformation of FadR, making it unable to bind to the DNA sequence it recognizes. To our knowledge, there is no promoter exists in nature that can respond solely to FadR since those promoters are often regulated by glucose concentration or oxidative stress and many other factors.
Contribution: WHU-China 2021
Previous analysis of fadR found that its N-terminus binds DNA, and C-terminal domain binds acyl-CoA. And pFadD_Lac is a fatty acid-sensitive promoter, one of the regulators in the enzymes of fatty acid biosynthesis in E. coli. It is composed of two fadR recognition sites. In the absence of fatty acids, an intrinsic transcription factor FadR acting as the repressor in the fatty acid metabolism system in E. coli. will attach to the promoter, and block the downstream gene expression. This has been proved to be effective by a previous iGEM team（NTHU_Taiwan）. [1][2]
2019 NTHU_Taiwan further modified pFadD promoter by replacing its CRP binding site with a LacI repressor binding site, which reduced expression leakage. You can find more information in BBa_K3040114.
Figure 1. pFadD_Lac promoter and fadR.
[1] https://2019.igem.org/Team:NTHU_Taiwan/Results
[2] http://2012.igem.org/Team:NTU-Taida#
Sequence and Features
- 10COMPATIBLE WITH RFC[10]
- 12COMPATIBLE WITH RFC[12]
- 21COMPATIBLE WITH RFC[21]
- 23COMPATIBLE WITH RFC[23]
- 25COMPATIBLE WITH RFC[25]
- 1000COMPATIBLE WITH RFC[1000]
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