Abstract: TyrR is a global regulatory protein in the amino acid biosynthesis and transport pathway of Escherichia coli（E. coli）, which controls the transcription of eight transcriptional units, including tyrP. Mutation of TyrR to tyrP was induced by site-directed mutagenesis of two RNAP（RNA polymerase）binding sites of the tyrP gene promoter, and the combination of TyrR and L-phenylalanine（L-Phe）greatly enhanced RNAP binding affinity on the downstream binding site（tyrP promoter）, so we can use L-Phe to control the promoter strength and then regulate the transcription level. In order to construct the L-Phe biosensor, the tyrP promoter was transformed into a measurable fluorescence value, and the tyrP promoter was used to construct the L-Phe biosensor. The intensity of tyrP promoter was controlled by L-Phe, and the intensity of tyrP promoter was changed. The intensity of tyrP promoter was changed in different degrees, and after L-Phe regulation, tyrP promoter intensity is also increased within a certain range with the concentration of L-Pheincreased. This is of great significance for the metabolic pathway of L-Phe production in E. coli, and it provides a new method for the construction of higher yield L-Phe strain.

Key words: TyrR, tyrP, L-Phenylalanine, biosensor, promoter intensity