FEATURES

DESCRIPTION

Also known as TYRR_ECOLI, tyrR. Involved in transcriptional regulation of aromatic amino acid biosynthesis and transport. Modulates the expression of at least 8 unlinked operons. Seven of these operons are regulated in response to changes in the concentration of the three aromatic amino acids (phenylalanine, tyrosine and tryptophan). These amino acids are suggested to act as co-effectors which bind to the TyrR protein to form an active regulatory protein. In most cases TyrR causes negative regulation, but positive effects on the tyrP gene have been observed at high phenylalanine concentrations. Homodimer. In presence of tyrosine (to the lesser extent, phenylalanine or tryptophan) and excess of ATP it undergoes a ligand-induced hexamerization. It is suggested that the hexameric form of TyrR is the active repressing species, interacting with two or three tyrR boxes in the targeted regulatory DNA.

EXTERNAL LINKS

tyrR

Mutations

Mutation(s) distribution

Mutations table