Revealing the catalytic residues of amorpha-4,11-diene synthase (ADS): new insight for engineering terpene synthases

Terpenoid, the largest group of specialized metabolites, exhibits a wide range of functional roles and bioactivities (1,2). The condensation of five-carbon terpenoid building blocks [isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP)], together with the further addition of IPP, leads to the generation of various sizes of common terpenoid precursors. These precursors are then converted into several types of terpenoid classified based on the number of C5-isoprene units in the structure, for example, hemiterpenoids (C5), monoterpenoids (C10), sesquiterpenoids (C15), diterpenoids (C20), sesterterpenoids (C25), and triterpenoids (C30).