Part:BBa_K1166001

Fumarate-Nitrate Reductase

FNR (fumarate nitrate reductase regulator) is a transcriptional regulator that functions as an O2 sensor. Under anoxic conditions FNR is in the active state and is found as a homodimer. When O2 is present FNR is converted into a monomer which is no longer active (Reinhart, et al., 2008). Therefore, co-expression of FNR with genes regulated by hypoxic promoters bearing a FNR binding site would help to have a more sensitive hypoxic response. Activity is proven by comparing the expression of GFP (BBa_E0040) by promoters with and without the simultaneous expression of the FNR protein.

The graphic shows the effect of FNR in the promoter nirB. When GFP is expressed under the regulation of nirB and without FNR (pNG) the same basal fluorescence is detected through many oxygen levels, on the other hand, when FNR is expressed, a rise in fluorescence is observed at hypoxic conditions.

References

Reinhart F, Achebach S, Koch T, Unden G. (2008). Reduced apo-fumarate nitrate reductase regulator (apoFNR) as the major form of FNR in aerobically growing Escherichia coli. J Bacteriol. 190(3):879-86.

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]