A Plant Type Ⅲ Polyketide Synthase that Produces Pentaketide Chromone

摘要

A. arborescens PCS is a novel plant-specific type Ⅲ PKS that produces an aromatic pentaketide from five molecules of malony-CoA. Site-directed mutagenesis revealed that Met207 determines the polyketide chain length and the product specificity; PCS M207G mutant yielded SEK4 and SEK4b from eight molecules of malonyl-CoA. This provided new insights into the catalytic functions and specificities of type Ⅲ PKSs. Further characterization of the enzymes including their three-dimensional structure will be reported in due course.