An engineered chorismate mutase with allosteric regulation.

Besides playing a central role in phenylalanine biosynthesis, the bifunctional P-protein in Eschericia coli provides a unique model system for investigating whether allosteric effects can be engineered into protein catalysts using modular regulatory elements. Previous studies have established that the P-protein contains three distinct domains whose functions are preserved, even when separated: chorismate mutase (residues 1-109), prephenate dehydratase (residues 101-285), and an allosteric domain (residues 286-386) for feedback inhibition by phenylalanine. By deleting the prephenate dehydrase domain, a functional chorismate mutase linked directly to the phenylalanine binding domain has been engineered and overexpressed. This manuscript reports the catalytic properties of the mutase in the absence and presence of phenylalanine.