Sinapoyltransferases in the light of molecular evolution

Brassicaceous species developed acyltransferases that accept in the formation of sinapate esters 1-O-glucose esters as acyl donors, typically 1-O-sinapoyl-β-glucose, as an alternative to the ubiquitously occurring CoA-thioester-dependent enzymes. These transferases most likely evolved from a hydrolytic ancestor of the serine carboxypeptidase type. We have analyzed structure-function relationships, reaction mechanism and sequence evolution of Arabidopsis 1-O-sinapoyl-β-glucose:l-malate sinapoyltransferase (AtSMT) to investigate molecular changes required to impart acyltransferase activity to hydrolytic enzymes.