Characterization of an aromatic O-prenyltransferase from the edible mushroom Sparassis crispa

ABSTRACT

Prenylated plant phenolics are a large group of secondary metabolites known for their bioactivity that is beneficial for plant and human alike, for example as antimicrobial agents against pathogenic microbes. However, the limited availability of prenylated phenolics, especially O-prenylated phenolics, and the complexity of the plant metabolite mixtures hinder bioactivity studies and further application. To explore approaches for more efficient production of prenylated phenolics, we produced and characterized a novel prenyltransferase (ScPTMY) from the edible mushroom Sparassis crispa. ScPTMY belongs to the dimethylallyl tryptophan synthase (DMATS) family and was found to primarily catalyze O-prenylation of structurally diverse phenolics. The best substrates included l-tryptophan, l-tyrosine, stilbenes, and isoflavonoids. The ScPTMY reactions predominantly yielded a single mono-O-prenylated product with an exception of the isoflavonoids, for which more products were obtained, including di-prenylated ones. Notably, we demonstrated the potential of this O-prenylating DMATS to enhance bioactivity by showing that enzymatic O4'-prenylation conferred antimicrobial activity to resveratrol, a compound with otherwise very poor antimicrobial activity. Finally, our phylogenetic analysis suggested the possibility of combining evolutionary relationships with structural insights to predict substrate scope and regioselectivity, while also revealing seven largely unexplored fungal DMATS clades that may harbor novel functions for biotechnological applications.