Divergent Biosynthesis of Fungal Dioxafenestrane Sesquiterpenes by the Cooperation of Distinctive Baeyer–Villiger Monooxygenases and α-Ketoglutarate-Dependent Dioxygenases

Abstract

Divergent biosynthesis is widely employed in nature to promote chemical diversity, usually depending on multifunctional enzymes from different environments, for the generation of diverse biologically active compounds. In this work, we identified two parallel and complex pathways (peni and aspe) of fungal dioxafenestrane sesquiterpenes from terrestrial fungus and marine-derived fungus, respectively. These two pathways share a common intermediate but are different in late-stage tailoring steps such as Baeyer–Villiger oxidation in δ-lactone formation and hydroxylation carried on nonactivated carbons. It is important that a distinctive Baeyer–Villiger monooxygenase (BVMO) AspeB from a marine-derived fungus source and a large number of substrate-tolerant α-ketoglutarate-dependent dioxygenases (α-KGDs, AspeC/D, and PeniD/F) and their artificial mutants used for structural diversity are discovered. Moreover, an acetylation step catalyzed by the acetyltransferase PeniE in the peni pathway was also identified. Our work not only reveals a representative example of the evolutionary relationship between natural product generation and corresponding metabolic enzymes from different environments but also provides valuable biocatalysts for nonactivated carbon oxidation modification.