Oxidosqualene Cyclases Involved in the Biosynthesis of Diverse Triterpenes in Camellia sasanqua
Oxidosqualene Cyclases Involved in the Biosynthesis of Diverse Triterpenes in Camellia sasanqua
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氧化角鲨烯环化酶参与茶梅多种三萜生物合成
DOI：
10.1021/acs.jafc.2c03011
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Lixin Duan
中科院分区：
文献类型：
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作者：
Liufang Huang;Yonger Hu;Ruoshi Huang;Jiabo Chen;Xi;e Zhang;Jingyang Yue;Laibao Feng;Yaru She;Aijia Ji;Ying Zheng;Zhongqiu Liu;Rong-Rong Zhang;Lixin Duan
茶梅是一种重要的经济植物，富含亲脂性三萜醇，具有抗过敏、抗炎、抗癌等药理活性。然而，茶梅中与三萜生物合成相关的关键酶却鲜有研究。氧化角鲨烯环化酶（OSC）是与三萜生物合成相关的限速酶。在这项研究中，从茶梅转录组中挖掘了七个假定的 OSC 基因 (CsOSC1-7)。通过异源表达系统对 6 个 CsOSC 进行了生物合成不同三萜骨架的表征，包括 α-香树脂醇、β-香树脂醇、δ-香树脂醇、达马烯二醇-II、ψ-蒲公英甾醇、蒲公英甾醇和环木菠萝烯醇。 CsOSC3 是一种多功能 α-香树脂醇合酶。从分子对接和定点突变的结果来看，三个关键残基Trp260、Tyr262和Phe415对于CsOSC3的催化性能至关重要。这些发现为茶梅中三萜的生物合成途径提供了重要的见解。
Camellia sasanqua is an important economic plant that is rich in lipophilic triterpenols with pharmacological activities including antiallergic, anti-inflammatory, and anticancer activities. However, the key enzymes related to triterpene biosynthesis have seldom been studied in C. sasanqua. Oxidosqualene cyclases (OSCs) are the rate-limiting enzymes related to triterpene biosynthesis. In this study, seven putative OSC genes (CsOSC1-7) were mined from the C. sasanqua transcriptome. Six CsOSCs were characterized for the biosynthesis of diverse triterpene skeletons, including α-amyrin, β-amyrin, δ-amyrin, dammarenediol-II, ψ-taraxasterol, taraxasterol, and cycloartenol by the heterologous expression system. CsOSC3 was a multiple functional α-amyrin synthase. Three key residues, Trp260, Tyr262, and Phe415, are critical to the catalytic performance of CsOSC3 judging from the results of molecular docking and site-directed mutagenesis. These findings provide important insights into the biosynthesis pathway of triterpenes in C. sasanqua.