How can the diterpene synthase CotB2V80L alter the product profile?

Abstract

Structural diversity of diterpenes is mediated by the enigmatic family of diterpene synthases. The overall enzymatic contribution hereby lies in a carefully concerted chemistry of highly reactive carbocation intermediates mainly guided by aromatic and polar amino acid side chains and the pyrophosphate cofactor. To date several studies aimed to shed light on the mechanism underlining terpene synthases chemistry. Specifically, the diterpene synthase CotB2 serves as model enzyme for detailed mutagenesis studies. Here we investigate the catalytic mechanism of CotB2 variant V80L in a holistic, biochemical, structural, and computational biology approach. We were able to identify an altered product profile compared to CotB2WT for the substrates geranylgeranyl diphosphate and farnesyl diphosphate. Moreover, we solved the crystal structure, and shed further light on terpene synthase chemistry by modelling of the substrate and intermediate binding.