Prenylation of dimeric cyclo-l-Trp-l-Trp by the promiscuous cyclo-l-Trp-l-Ala prenyltransferase EchPT1

Prenyltransferases (PTs) from the dimethylallyl tryptophan synthase (DMATS) superfamily are known as efficient biocatalysts and mainly catalyze regioselective Friedel-Crafts alkylation of tryptophan and tryptophan-containing cyclodipeptides (CDPs). They can also use other unnatural aromatic compounds as substrates and play therefore a pivotal role in increasing structural diversity and biological activities of a broad range of natural and unnatural products. In recent years, several prenylated dimeric CDPs have been identified with wide range of bioactivities. In this study, we demonstrate the production of prenylated dimeric CDPs by chemoenzymatic synthesis with a known promiscuous enzyme EchPT1, which uses cyclol-Trp-l-Ala as natural substrate for reverse C2-prenylation. High product yields were achieved with EchPT1 for C3-N1' and C3-C3' linked dimers of cyclo-l-Trp-l-Trp. Isolation and structural elucidation confirmed the product structures to be reversely C19/C19'-mono- and diprenylated cyclo-l-Trp-l-Trp dimers. Our study provides an additional example for increasing structural diversity by prenylation of complex substrates with known biosynthetic enzymes.

Automated summary

Prenyltransferases (PTs) are efficient biocatalysts that catalyze the regioselective alkylation of tryptophan and its derivatives, increasing the structural diversity and biological activities of natural and unnatural products. Recent studies have identified prenylated dimeric cyclodipeptides (CDPs) with a wide range of bioactivities. This study demonstrates the chemoenzymatic synthesis of prenylated dimeric CDPs using the promiscuous enzyme EchPT1, resulting in the production of reversely prenylated cyclo-l-Trp-l-Trp dimers.