Pinpointing the L-phenylalanine binding sites of TyrR using biosensors and computer-aided simulation.

OBJECTIVES: To determine the binding sites for L-phenylalanine in TyrR protein via a rational mutation analysis combining biosensors and computer-aided simulation. RESULTS: TyrR protein of Escherichia coli is the chief transcriptional regulator of several genes essential for the biosynthesis and transport of aromatic amino acids. The identification of ligand-binding sites is often the starting point for protein function annotation and structure-based protein design. Here we combined computer-aided prediction methods and biosensors to identify the ligand-binding sites for L-Phe in TyrR protein. CONCLUSIONS: Residues at positions 160, 173 and 184 of TyrR protein are important for transcriptional activation of target genes tyrP induced by L-Phe, which indicates that they are the bona fide L-Phe binding sites of TyrR protein.