title: Molecular characterization of a membrane-bound prenyltransferase specific for isoflavone from Sophora flavescens.
abstract: Prenylated isoflavones are secondary metabolites that are mainly distributed in legume plants. They often possess divergent biological activities such as anti-bacterial, anti-fungal, and anti-oxidant activities and thus attract much attention in food, medicinal, and agricultural research fields. Prenyltransferase is the key enzyme in the biosynthesis of prenylated flavonoids by catalyzing a rate-limiting step, i.e. the coupling process of two major metabolic pathways, the isoprenoid pathway and shikimate/polyketide pathway. However, so far only two genes have been isolated as prenyltransferases involved in the biosynthesis of prenylated flavonoids, namely naringenin 8-dimethylallyltransferase from Sophora flavescens (SfN8DT-1) specific for some limited flavanones and glycinol 4-dimethylallyltransferase from Glycine max (G4DT), specific for pterocarpan substrate. We have in this study isolated two novel genes coding for membrane-bound flavonoid prenyltransferases from S. flavescens, an isoflavone-specific prenyltransferase (SfG6DT) responsible for the prenylation of the genistein at the 6-position and a chalcone-specific prenyltransferase designated as isoliquiritigenin dimethylallyltransferase (SfiLDT). These prenyltransferases were enzymatically characterized using a yeast expression system. Analysis on the substrate specificity of chimeric enzymes between SfN8DT-1 and SfG6DT suggested that the determinant region for the specificity of the flavonoids was the domain neighboring the fifth transmembrane α-helix of the prenyltransferases.
authors.affiliation: Laboratory of Plant Gene Expression, Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Kyoto 611-0011, Japan.
authors.forename: Kanako
authors.initials: K
authors.lastname: Sasaki
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Tsurumaru
authors.forename: Hirobumi
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Kazufumi
authors.initials: K
authors.lastname: Yazaki
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D019833:Genistein / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D054876:Prenylation / Q000502:physiology*; D029909:Sophora / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity / Q000502:physiology
chemical_list: D008565:Membrane Proteins; D010940:Plant Proteins; D019833:Genistein; D019883:Alkyl and Aryl Transferases