Three carbon-/oxygen-prenyltransferases responsible for furanocoumarin synthesis in Angelica dahurica

Abstract

As a popular medicinal plant, Angelica dahurica has been attached to great importance in herbal medicine. Its main active compounds are furanocoumarins (FCs) including imperatorin and isoimperator which exhibit anti-oxidant, anti-tumor, and anti-virus activities. However, the enzymes catalyzing the crucial step of FCs’ biosynthesis pathway remain unidentified. This study initially screened six prenyltransferases (PTs)-coding sequences through transcriptome and gene expression profile analysis. Combined with qRT-PCR and in vitro enzyme activity verification, two C-PTs (AdPT1, 2) which convert umbelliferone to 7-demethylsuberosin (DMS), and one O-PT (AdPT3) which transforms xanthotoxol to imperatorin were identified. Among these PTs, AdPT2 also produces a trace amount of osthenol from umbelliferone. Homologous modeling, molecular docking, and site-directed mutagenesis analysis were also conducted and it is discovered that Asp301 and Asp305 in the two Asp-rich regions are vital for the activity of AdPT1. The study is the first to conduct a frontier exploration of the biosynthesis pathways of FCs in A. dahurica and will establish a foundation for the molecular mechanism of further C-PTs and O-PTs evolutionary studies. Data and materials availabilityAll data needed to evaluate the conclusions in this paper are present in the paper and/or in supplementary. the accession numbers of AdPT1–3 are OP753387-OP733389, the raw RNA sequence reads are available as SRP289220.