Mutational analysis of the feedback sites of phenylalanine-sensitive 3-deoxy-D-arabino-heptulosonate-7-phosphate synthase of Escherichia coli

In Escherichia coli, aroF, aroG, and aroH encode 3-deoxy-D-arabino-heptulosonate-7-phosphate synthase isozymes that are feedback inhibited by tyrosine, phenylalanine, and tryptophan, respectively. In vitro chemical mutagenesis of the cloned aroG gene was used to identify residues and regions of the polypeptide essential for phenylalanine feedback inhibition.