Modification of the dynamic nature of the chimeric fumarate two-component system in Escherichia coli via positive feedback loop

A positive feedback loop was introduced to modify the dynamic behavior of fumarate sensing DcuSZ chimera TCS. To construct the positive feedback loop, the ompR gene was cloned downstream of the ompC promoter. The ompC promoter induced the expression of OmpR, which in turn induced the expression of the ompC promoter. Through the introduction of this positive feedback loop, the transcriptional expression levels of ompC increased 2.6-fold. When GFP was used as a reporter protein, a 64% increase in fluorescence level was observed. These results suggest that sensitivity of the TCS based fumarate sensing system can be engineered through the introduction of a positive feedback loop.