Part:BBa_K554003

SoxR

SoxR is a transcription factor found in bacteria and is activated during superoxide or nitric oxide stress. SoxR protein in solution is a homodimer that contains two binuclear iron–sulfur clusters ([2Fe–2S]) which are then oxidized upon superoxide stress. In this form, the protein induces transcription through binding at SoxS promoter. Thus, in the presence of NO, SoxR activates transcription of the gene regulated by SoxS promoter (Hidalgo et al, 1998).

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
  COMPATIBLE WITH RFC[25]
• 1000
  COMPATIBLE WITH RFC[1000]

Usage and Biology

The [2Fe-2S] SoxR transcription factor a member of MerR family and is an important sensor of oxidative stress in bacteria, turning activated under presence of superoxide and nitric oxide (NO). SoxR is activated by reversible one-electron oxidation of its [2Fe-2S] cluster and in the active state, SoxR activate transcription of genes containing SoxS promoter, which have a long 19- or 20-bp spacer between the -35 and -10 operator elements, by untwisting the promoter DNA (Watanabe et al. 2008). The SoxR gene is used by [http://2011.igem.org/Team:UNICAMP-EMSE_Brazil UNICAMP-EMSE Brazil team] in the [http://2011.igem.org/Team:UNICAMP-EMSE_Brazil/Project#Device_2:_NO_sensor.2FIL-10_producer NO sensor device/ IL-10 producer] ("Device 2", which senses NO levels and responds by producing and secreting IL-10). This part is shown in the following schema:

Three-dimensional structure representation

You can find below a tridimensional structure of Escherichia coli SoxR protein bound to SoxS promoter (DNA structure) (retrieved from PDB 2zhg, Watanabe et al. 2008). This is a jmol applet, in which you can interactively see part of the SoxS promoter bound to its regulatory protein SoxR in a 3D manner:

References

1. Watanabe S, Kita A, Kobayashi K, Miki K. Crystal structure of the [2Fe-2S] oxidative-stress sensor SoxR bound to DNA.Proc Natl Acad Sci U S A. 2008 Mar 18;105(11):4121-6. Epub 2008 Mar 11. [http://www.ncbi.nlm.nih.gov/pubmed/18334645 Link to PubMed]
2. Hidalgo E, Leautaud V, Demple B (1998) The redox-regulated SoxR protein acts from a single DNA site as a repressor and an allosteric activator. The EMBO Journal 17(9)2629–2636 [http://www.ncbi.nlm.nih.gov/pubmed/?term=9564045%20 Link to Pubmed]