Exploring evolutionary use of single residue switches for alternative product outcome in class II diterpene cyclases.

Class II diterpene cyclases (DTCs) define the widespread labdane-related diterpenoids. These are particularly prevalent in plants due to the requisite production of gibberellin (GA) phytohormones, specifically from gene duplication and neofunctionalization of the relevant DTC. Alteration of product outcome can be predicted/engineered to some extent by changes in the ancestral histidine-asparagine catalytic base dyad found in the ent-copalyl pyrophosphate (ent-CPP) synthases (CPSs) involved in GA biosynthesis.