Feedback-insensitive mutation of 3-deoxy-d-arabino-hepturosonate-7-phosphate synthase caused by a single nucleotide substitution of ARO4 structural gene in Saccharomyces cerevisiae

The Saccharomyces cerevisiae ARO4 gene product 3-deoxy- d - arabino -hepturosonate-7-phosphate (DAHP) synthase (EC 4.1.2.15), the first common enzyme in aromatic amino acid biosynthesis, is subject to feedback inhibition by tyrosine. A mutated ARO4 gene for feedback-insensitive DAHP synthase which causes both o -fluoro- dl -phenylalanine-resistance and β -phenethyl-alcohol-overproduction was cloned. The DNA sequence of the mutant gene revealed a single nucleotide difference in the structural region from its wild-type gene. The mutation results in a glutamine-to-lysine amino acid substitution in the DAHP synthase.