GuA6DT, a Regiospecific Prenyltransferase from Glycyrrhiza uralensis, Catalyzes the 6‐Prenylation of Flavones

Abstract

GuA6DT, a flavonoid prenyltransferase, was identified from Glycyrrhiza uralensis, and it was found that this enzyme regiospecifically transfers a dimethylallyl moiety to apigenin at the C-6 position. A further substrate specificity investigation indicated that the existence of hydroxyls at both the C-5 and C-7 positions of the flavone skeleton is critical for the prenylation. However, substitutions on the B-ring had negligible influence on the prenylation. A comparison of GuA6DT expression in different organs revealed that mRNA is mainly expressed in the aerial parts. Moreover, the GuA6DT mRNA was found to be regulated at the transcriptional level, because methyl jasmonate induced upregulation in cultured cells. GuA6DT is the first identified flavone prenyltransferase to exhibit strict substrate specificity and regiospecificity.

Molecular Characterization and Phylogenetic Analysis of Two Novel Regio-specific Flavonoid Prenyltransferases from Morus alba and Cudrania tricuspidata

“…Therefore, we initially hypothesized that the FPTs of M. alba would cluster together with the leguminous FPTs and used degenerated primer pairs based on these FPTs to clone the candidate gene(s). Similar cloning strategies proved to be successful in the isolation of SfFPT and GuA6DT from S. flavescens and Glycyrrhiza uralensis in our previous work (14,15). However, after RT-PCR and RACE, we failed to achieve active PTs.…”

“…The HPLC-UV/ESI-MS analyses of the enzymatic products were performed as previously described (15) with the exception that the solvent system consisted of a linear gradient from 50% to 100% (v/v) methanol in water with 0.1% formic acid over a period of 30 min followed by an isocratic elution with 100% methanol for 10 min and that the UV detector was set at 350 or 265 nm. For the isolation of the enzymatic products, an approach similar to that previously described was employed (15) with the exception that the semi-preparative reverse-phase HPLC was performed using a linear gradient from 50% to 100% (v/v) methanol in water over a period of 20 min.…”

“…The microsomal fractions of YPH499 expressing pESC-HIS-MaIDT and pESC-HIS-CtIDT were prepared as previously described (14,15) and resuspended in 100 mM Tris-HCl (pH 9.0). The total protein concentration was determined by the Bradford method (30).…”

“…These observations indicated that FPTs existed in the cell suspension cultures of each of the two plants. Therefore, in our ongoing work on plant FPTs (14,15), cell suspension cultures of M. alba and C. tricuspidata were selected as materials from which to isolate non-Leguminosae FPTs.…”

A Stilbenoid-Specific Prenyltransferase Utilizes Dimethylallyl Pyrophosphate from the Plastidic Terpenoid Pathway

“…This enzyme catalyzes the dimethylallylation of glycinol at position 4 to produce the precursor of the phytoalexin, glyceollin I (Akashi et al, 2009). More recently, GuA6DT, a flavone prenyltransferase, was identified in another legume species, liquorice (Glycyrrhiza uralensis; Li et al, 2014), and SfFPT characterized from S. flavescens displays high catalytic efficiency of C-8 prenylation on different types of flavonoids, including flavanone, flavone, and flavanonol (Chen et al, 2013).…”