![](https://parts.igem.org/images/partbypart/icon_coding.png)
Part:BBa_K4115002
NifA(nif-specific transcriptional activator)
The coding sequence of the nifA protein in the nitrogen-fixing gene cluster.
The nifA protein encoded by the nifA sequence is a transcriptional activator that can activate the transcription of the downstream nifH promoter under the influence of cytosolic nitrogen sources or oxygen, and is a key activator of nitrogen-fixing gene clusters. The nitrogen fixation gene can be regulated by knocking out the native nifA sequence and replacing it with the nifA sequence added with regulatory elements.
Sequence and Features
- 10INCOMPATIBLE WITH RFC[10]Illegal PstI site found at 136
Illegal PstI site found at 1000 - 12INCOMPATIBLE WITH RFC[12]Unknown
- 21INCOMPATIBLE WITH RFC[21]Illegal BamHI site found at 637
- 23INCOMPATIBLE WITH RFC[23]Unknown
- 25INCOMPATIBLE WITH RFC[25]Illegal PstI site found at 136
Illegal PstI site found at 1000
Illegal NgoMIV site found at 1257
Illegal NgoMIV site found at 1452
Illegal NgoMIV site found at 1527
Illegal AgeI site found at 886 - 1000INCOMPATIBLE WITH RFC[1000]Illegal BsaI site found at 1095
Illegal SapI site found at 318
Illegal SapI site found at 939
Usage and Biology
The A. caulinodans nif cluster is difficult to engineer because it is large (64 kb total, 76 genes), distributed across multiple loci and has a complex regulatory network.
Fortunately, studies have shown that the expression level of nitrogen fixation genes can be efficiently regulated by regulating the expression of a single gene corresponding to nifA. [1]
Therefore, we followed the regulatory scheme pointed out in the literature, knocked out the original nifA gene of nitrogen-fixing bacteria regulated by ammonium root and replaced it with the nifA coding sequence regulated by other artificially designed parts. The expressed protein then activates the downstream receiving part PnifHBBa_K4115014, which in turn regulates the nif gene cluster (nitrogen-fixing gene cluster).
![](/wiki/images/8/86/Control_of_nitrogen_fixation_in_A_caulinodans_ORS571.jpg)
[1]Ryu, M. H., Zhang, J., Toth, T., Khokhani, D., Geddes, B. A., Mus, F., Garcia-Costas, A., Peters, J. W., Poole, P. S., Ané, J. M., & Voigt, C. A. (2020). Control of nitrogen fixation in bacteria that associate with cereals. Nature microbiology, 5(2), 314–330. https://doi.org/10.1038/s41564-019-0631-2
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