Cloning and characterization of naringenin 8-prenyltransferase, a flavonoid-specific prenyltransferase of Sophora flavescens
Cloning and characterization of naringenin 8-prenyltransferase, a flavonoid-specific prenyltransferase of Sophora flavescens
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DOI：
10.1104/pp.107.110544
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发表时间：
2008-03-01
期刊：
影响因子：
7.4
通讯作者：
Yazaki, Kazufumi
中科院分区：
文献类型：
--
作者：
Sasaki, Kanako;Mito, Kouji;Yazaki, Kazufumi
异戊烯化类黄酮是天然化合物，通常代表各种药用植物中的活性成分，并对人类健康具有有益作用。异戊烯化的类黄酮是由主要连接到来自类异戊二烯（萜类）代谢的5-碳（二甲基烯丙基）或10-碳（香叶基）异戊烯基的类黄酮核心组成的杂合产物，并且异戊烯基对其生物活性至关重要。体内异戊烯化反应是两种主要代谢途径（什基酯-乙酸酯途径和类异戊二烯途径）的关键偶联过程，其中这些反应也被称为限速步骤。然而，尽管在这一领域进行了30多年的研究，但尚未确定负责类黄酮异戊二烯化的基因。我们已经从苦参中分离出异戊二烯基转移酶基因SfN 8DT-1，该基因负责黄酮类化合物柚皮素在8位的异戊二烯化，该基因对作为底物的黄烷酮和二甲基烯丙基二磷酸具有特异性。系统发育分析表明，SfN 8DT-1与维生素E和质体醌的异戊二烯基转移酶具有相同的进化起源。SfN 8DT-1的基因表达严格限于根皮，其中异戊二烯化的黄酮类化合物仅在植物中积累。SfN 8DT-1在拟南芥中的异位表达导致异戊二烯化芹菜素、槲皮素和山奈酚以及8-异戊二烯基柚皮素的形成。SfN 8DT-1代表了植物中鉴定的第一个类黄酮特异性异戊二烯基转移酶，并为鉴定和表征负责生产这一重要的次级代谢产物的其他基因铺平了道路。
Prenylated flavonoids are natural compounds that often represent the active components in various medicinal plants and exhibit beneficial effects on human health. Prenylated flavonoids are hybrid products composed of a flavonoid core mainly attached to either 5-carbon (dimethylallyl) or 10-carbon (geranyl) prenyl groups derived from isoprenoid (terpenoid) metabolism, and the prenyl groups are crucial for their biological activity. Prenylation reactions in vivo are crucial coupling processes of two major metabolic pathways, the shikimate-acetate and isoprenoid pathways, in which these reactions are also known as a rate- limiting step. However, none of the genes responsible for the prenylation of flavonoids has been identified despite more than 30 years of research in this field. We have isolated a prenyltransferase gene from Sophora flavescens, SfN8DT-1, responsible for the prenylation of the flavonoid naringenin at the 8-position, which is specific for flavanones and dimethylallyl diphosphate as substrates. Phylogenetic analysis shows that SfN8DT-1 has the same evolutionary origin as prenyltransferases for vitamin E and plastoquinone. The gene expression of SfN8DT-1 is strictly limited to the root bark where prenylated flavonoids are solely accumulated in planta. The ectopic expression of SfN8DT-1 in Arabidopsis thaliana resulted in the formation of prenylated apigenin, quercetin, and kaempferol, as well as 8-prenylnaringenin. SfN8DT-1 represents the first flavonoid-specific prenyltransferase identified in plants and paves the way for the identification and characterization of further genes responsible for the production of this large and important class of secondary metabolites.