Engineered geranyl diphosphate methyltransferase produces 2-methyl-dimethylallyl diphosphate as a noncanonical C6 unit for terpenoid biosynthesis

Chen-Yang Xia; Bo-Wen Lu; Ji-Yun Cui; Bai-Yang Wang; Yue-Yang Sun; Fei Gan

doi:10.1016/j.synbio.2022.12.002

Engineered geranyl diphosphate methyltransferase produces 2-methyl-dimethylallyl diphosphate as a noncanonical C₆ unit for terpenoid biosynthesis

Synth Syst Biotechnol. 2022 Dec 19;8(1):107-113. doi: 10.1016/j.synbio.2022.12.002. eCollection 2023 Mar.

Authors

Chen-Yang Xia¹, Bo-Wen Lu¹, Ji-Yun Cui¹, Bai-Yang Wang¹, Yue-Yang Sun¹, Fei Gan^{1

2

3}

Affiliations

¹ Hubei Key Laboratory of Cell Homeostasis, College of Life Science, Wuhan University, Wuhan, China.
² TaiKang Center for Life and Medical Science, Wuhan University, Wuhan, China.
³ Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, Wuhan, China.

Abstract

Terpenoids constitute the largest class of natural products with complex structures, essential functions, and versatile applications. Creation of new building blocks beyond the conventional five-carbon (C₅) units, dimethylallyl diphosphate (DMAPP) and isopentenyl diphosphate, expands significantly the chemical space of terpenoids. Structure-guided engineering of an S-adenosylmethionine-dependent geranyl diphosphate (GPP) C2-methyltransferase from Streptomyces coelicolor yielded variants converting DMAPP to a new C₆ unit, 2-methyl-DMAPP. Mutation of the Gly residue at the position 202 resulted in a smaller substrate-binding pocket to fit DMAPP instead of its native substrate GPP. Replacement of Phe residue at the position 222 with a Tyr residue contributed to DMAPP binding via hydrogen bond. Furthermore, using Escherichia coli as the chassis, we demonstrated that 2-methyl-DMAPP was accepted as a start unit to generate noncanonical trans- and cis-prenyl diphosphates (C_5n+1) and terpenoids. This work provides insights into substrate recognition of prenyl diphosphate methyltransferases, and strategies to diversify terpenoids by expanding the building block portfolio.

Keywords: Methyltransferase; Noncanonical building block; Protein engineering; Terpenoid biosynthesis.