Difference between revisions of "Part:BBa K1166001"

Latest revision as of 17:38, 4 October 2013

Fumarate-Nitrate Reductase This part includes the native expression cassette for FNR.

FNR (fumarate nitrate reductase regulator) is a transcriptional regulator that functions as an O2 sensor. Under hypixia FNR is in its 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 When O2 is present FNR is converted into a monomer which is no longer active (Reinhart, et al., 2008).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 (K1166000) in the promoter nirB (BBa_K905000). When GFP is expressed under the regulation of nirB (BBa_K905000) and without FNR (pNG=promoter nirb + GFP) the same basal fluorescence is detected through all oxygen levels, on the other hand, when FNR is co-expressed (pFG=FNR, promoter nirb+GFP), 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