Functional Characterization of Three Diterpene Synthases Responsible for Tetracyclic Diterpene Biosynthesis in Scoparia dulcis

Jung-Bum Lee; Tomoya Ohmura; Yoshimi Yamamura

doi:10.3390/plants12010069

Functional Characterization of Three Diterpene Synthases Responsible for Tetracyclic Diterpene Biosynthesis in Scoparia dulcis

Plants (Basel). 2022 Dec 23;12(1):69. doi: 10.3390/plants12010069.

Authors

Jung-Bum Lee¹, Tomoya Ohmura¹, Yoshimi Yamamura¹

Affiliation

¹ Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan.

Abstract

Scoparia dulcis produces unique biologically active diterpenoids such as scopadulcic acid B (SDB). They are biosynthesized from geranylgeranyl diphosphate (GGPP) via syn-copalyl diphosphate (syn-CPP) and scopadulanol as an important key intermediate. In this paper, we functionally characterized three diterpene synthases, SdCPS2, SdKSL1 and SdKSL2, from S. dulcis. The SdCPS2 catalyzed a cyclization reaction from GGPP to syn-CPP, and SdKSL1 did from syn-CPP to scopadulan-13α-ol. On the other hand, SdKSL2 was found to incorporate a non-sense mutation at 682. Therefore, we mutated the nucleotide residue from A to G in SdKSL2 to produce SdKSL2mut, and it was able to recover the catalytic function from syn-CPP to syn-aphidicol-16-ene, the precursor to scopadulin. From our results, SdCPS2 and SdKSL1 might be important key players for SDB biosynthesis in S. dulcis.

Keywords: Scoparia dulcis; cyclase; diterpene synthase.

Grants and funding

This study was financially supported by Grant-in-Aid for Scientific Research C (18K06729) from the Ministry of Education, Culture, Sports, Science, and Technology of Japan.