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TyrP promoter

Part Description

An exclusive transporter for tyrosine is encoded by the tyrP gene in Escherichia coli. Tyrosine inhibits it, whereas phenylalanine and, to a lesser extent, tryptophan activate it. Tyrosine also inhibits its production. The TyrR protein, which has two cognate binding sites (TyrR boxes) that span nucleotides 30 to 75, mediates both of these effects when it binds to one of both of these sites. A dimer that binds to the upstream box and interacts with the subunit (CTD) of RNA polymerase causes the activation in the presence of phenylalanine or tryptophan (RNAP). A hexamer binds to both TyrR boxes during repression in the presence of tyrosine.

Usage

TyrP promoter,normally regulate the expression for a part which codes for tyrosine-specific transport system, it is induced when phenylalanine and the tyrR gene product (TyrR dimer)are together ,taking advantage of that we use it to regulate the expression of PAH in our therapeutic circuit and ß-galactosidase in our diagnostic circuit.

Literature Characterization

TyrP prompter activity is mediated by the presence of TyrR protein, In this experiment,the change of TyrP promoter activity was measured according to the nature of different DNA templates.The TyrP promoter was significantly expanded in the supercoiled form in the presence of RNAP, indicating that RNAP forms a more stable complex with the supercoiled TyrP promoter. However, only mild opening was identified at the upstream binding site's 10 areas when linear template was present.

Figure.1 KMnO4 footprinting of linear and supercoiled templates

References

Sequence and Features