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Team:Korea U Seoul/Design
From 2010.igem.org
To sense heavy metals, we select promoters which are expressed in the presence of heavy metals. These promoters encode proteins maintaing cell conditions resistant to heavy metals. ParsR is promoter to arsenic and PzntA is for zinc. Low concentrations can have devastating effects, interfering with processes in the cell. Because of the similarity to phosphate, sometimes arsenate is mistaken for phosphate, which is how it is introduced into living organisms, including E. coli, by the phosphate uptake system. Other molecules such as As(III) can also be introduced into the cells by various membrane transporters. Cells have effective defenses to deal with elevated levels of arsenic variants, which are under the control of metal sensitive promoters. The transcription is mostly regulated by proteins binding to, or releasing from the promoter site, like ArsR. ArsR negatively controls the expression of the genes involved in arsenical and antimonite metals resistance, whose expression is induced in the presence of these metals.
In case of cadmium, there is no promoters encoding resistant to cadium directly. So we select Promoter yodA. At low cadmium concentrations, cells are able to adapt and resume growth after a period of stasis. Promoter yodA is only transiently activated during cadmium-induced growth inhibition. Aryl acylamidase is an enzyme that acts on the amide bond between aryl- and acyl groups. The most typical reaction is the hydrolysis of an anilide, producing a carboxylate and aniline, which is also reversible. Acetaminophen(Tyrenol) is an aryl acyl compound having amide bond is hydrolyzed by the enzyme and produce acetate and p-aminophenol. Because p-Aminophenol have red-purple color, aryl acylamidase gene will apply to reporter gene. Since aryl acylamidase gene(mAAA, BBa_K400628) is not registered to iGEM, we registered this gene.
