Part:BBa_K3771100
SoxR
Description
SoxR is a 17 kDa transcription factor of the MerR family. The normal in vivo level of SoxR protein is maintained at a low level of 50-100 molecules per cell, forming a dimer in solution. It contains a [2Fe–2S] cluster, which is essential for reversible one-electron oxidation and reduction to regulate its activity. Only when the [2Fe–2S] cluster is fully oxidized (Fe3+-Fe3+), SoxR becomes a powerful transcription activator of soxS promoter (up to 100-fold). Reducing the SoxR [2Fe–2S] cluster by one electron (Fe2+-Fe3+) can eliminate the ability to stimulate SoxS expression[1]. In response to superoxide-generating agents, SoxR is oxidized and activated, therefore increasing the synthesis of SoxS, which then activates its target gene expression[2].
Fig.1. The soxRS regulon. The soxRS regulon includes soxR and soxS genes. The soxR gene is expressed innately in cells and SoxR is activated in response to superoxide-generating agents and nitric oxide (NO). Oxidized SoxR acts as a transcriptional activator of soxS gene; SoxS, afterward, enhances the expression of antioxidant genes. Abbreviation: G6PD, glucose-6-P-dehydrogenase[1].
Usage and Biology
SoxR protein was used to regulate the expression of taurine-producing enzymes. When the [2Fe–2S] cluster is fully oxidized, SoxR acts as a strong transcription activator of soxS promoter[1]. The sequence of this basic part is the reverse complement of soxR gene from E. coli.
References
1. Pomposiello PJ, Demple B. Redox-operated genetic switches: the SoxR and OxyR transcription factors. Trends Biotechnol. 2001;19(3):109-114. doi:10.1016/s0167-7799(00)01542-0
2. Koo MS, Lee JH, Rah SY, et al. A reducing system of the superoxide sensor SoxR in Escherichia coli. EMBO J. 2003;22(11):2614-2622. doi:10.1093/emboj/cdg252
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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