Sun R, Gao J L, Chen H, Liu S, Tang Z Z
College of Life Science, Sichuan Agricultural University, Ya'an, Sichuan, 625014 China.
College of Biological and Chemical Engineering, Panzhihua University, Panzhihua, Sichuan, 617000 China.
Mol Biol (Mosk). 2020 Sep-Oct;54(5):813-825. doi: 10.31857/S0026898420050092.
Conyzasaponins produced by the traditional Chinese herb Conyza blinii are oleanane-type saponins with a wide range of biological activities. Here, we identified a gene, designated CbCYP716A261, encoding a β-amyrin 28-hydroxylase in conyzasaponins biosynthesis. Ten full putative CYP sequences were isolated from Conyza blinii transcript tags. The CbCYP716A261 gene product was selected as the putative β-amyrin 28-hydroxylase by phylogenetic analysis and transcriptional activity analysis of methyl jasmonate-treated Conyza blinii. To identify the enzymatic activity, we performed enzymatic activity experiments in vitro and in vivo. The HPLC results revealed that CbCYP716A261 catalyzes the hydroxylation of β-amyrin at the C-28 position to yield oleanolic acid. Our findings provide new information about the conyzasaponin biosynthesis pathway and widen the list of isolated β-amyrin 28-hydroxylases.
传统中草药布林旋覆花（Conyza blinii）产生的旋覆花皂苷是具有广泛生物活性的齐墩果烷型皂苷。在此，我们鉴定了一个名为CbCYP716A261的基因，其在旋覆花皂苷生物合成中编码一种β-香树脂醇28-羟化酶。从布林旋覆花转录本标签中分离出10个完整的假定CYP序列。通过系统发育分析和茉莉酸甲酯处理的布林旋覆花的转录活性分析，选择CbCYP716A261基因产物作为假定的β-香树脂醇28-羟化酶。为了鉴定酶活性，我们进行了体外和体内酶活性实验。高效液相色谱结果显示，CbCYP716A261催化β-香树脂醇在C-28位的羟基化反应生成齐墩果酸。我们的研究结果为旋覆花皂苷生物合成途径提供了新信息，并拓宽了已分离的β-香树脂醇28-羟化酶的范围。
