PAD1 ENCODES PHENYLACRYLIC ACID DECARBOXYLASE WHICH CONFERS RESISTANCE TO CINNAMIC ACID IN SACCHAROMYCES-CEREVISIAE

The yeast enzyme phenylacrylic acid decarboxylase (PAD) confers resist ance to phenylacrylic acids. Cinnamic acid (CA)-sensitive mutants lack ing PAD activity were isolated and the PADI gene was cloned by phenoty pic complementation. The nucleotide sequence of the smallest complemen ting fragment was determined. The predicted 242-amino-acid PAD polypep tide is 48.6% identical to the product of decF of Escherichia coli. PA D activity and CA resistance, but not steady-state PAD1 mRNA levels, a re influenced by mitochondrial genotype. PADI is a single-copy gene in the yeast genome and not essential for viability. The PADI locus was physically mapped to a position approx. 140 kb from the left end of ch romosome IV.