Revision as of 03:34, 22 October 2019

ompW Promoter

The promoter ompW is regulated by the inhibitor protein ArcA in the presence of 4mM hydrogen peroxide. Also ompW promother is inhibited by ArcA protein under anaerobic conditions.

This part was obtained from Salmonella enterica

Biology

Anaerobiosis, is a predominant physiological adaptation and it is mediated by the Aerobic respiratory control B (ArcAB). The two-component system ArcA/B senses the redox status in the cytoplasmic membrane of bacteria through its membrane sensor ArcB, and upon activated, primarily represses the expression of genes involved in the aerobic carbon oxidation through its cognate response regulator ArcA which is phosphorylated under this conditions and its active. Furthermore, bacterium as Salmonella enterica must sense H2O2 and modulate gene expression. ArcA/B system plays a role in the resistance to reactive oxygen species, under high H202 concentrations ArcA is activated and some targets, as ompW promoter, are negatively regulated.

Experiments

In order to test the ompW promoter works in E. coli we construct the biobrick BBa_K3238004 to report the GFP protein. In aerobic conditions we would look GFP expression if the promoter works in E. coli, however, if there is no GFP expression this part do not work in E. coli. If the part works, the addition of H2O2 would show us dismiss in the GFP expression rate, change E. coli to an anaerobic condition would have the same result.

Results

We observe GFP expression under aerobic conditions.

The culture of E. coli in anaerobic conditions and the addition of H202 do not show decrease in the GFP expression rate.

Conclution

We did not observe a GFP decrease expression under anaerobic and H202 conditions probably because the binding site of ArcA of Salmonella enterica is significantly different to the ArcA target from E. coli.

Sequence and Features