Molecular and biochemical characterization of a novel hydroxycinnamoyl-CoA: Anthocyanin 3-O-glucoside-6 ''-O-acyltransferase from Perilla frutescens

We have isolated and characterized a cDNA, PfAT208, encoding hydroxycinnamo yl-CoA: anthocyanin 3-O-glucoside-6 "-O-acyltransferase (3AT) from Perilla frutescens, The identity of the cDNA was established by determination of th e reaction products with recombinant enzyme overexpressed in Escherichia co il. The deduced amino acid sequence has a few regions that are conserved in a CoA-dependent acyltransferase family. The recombinant enzyme produced in yeast could utilize cyanidin 3-glucoside and cyanidin 3,5-diglucoside, put ative substrates in vivo, as well as other anthocyanins. The inhibitory eff ects of diethyl pyrocarbonate and N-ethylmaleimide on the recombinant 3AT a ctivities suggest that histidine and cysteine residues are important for th eir catalytic function. These properties are in common with anthocyanin 5-O -glucoside-6 "-O-acyltransferase (5AT), In Northern analysis, a transcript of PfAT208 was detected in the young leaves of perilla red forma. The prope rties of other cDNAs, gentian GAT106 and petunia PhAT48, isolated during th e above cloning procedure are also described.