Euphol is a euphane-type tetracyclic triterpene which is primarily found in the Euphorbia genus. Euphol has been renowned because of its great potential as a promising anticancer drug. Surprisingly, despite its diverse antitumor effects, the respective gene for euphol biosynthesis had not been identified until this study. In our experiments with Euphorbia tirucalli, euphol was detected predominantly in latex, the element that is often used for cancer treatments in Brazil. Two latex-specifically expressed oxidosqualene cyclases (OSCs) from E. tirucalli, designated as EtOSC5 and EtOSC6, were functionally characterized by expression in a lanosterol synthase knockout yeast strain GIL77. EtOSC5 produces euphol and its 20S-isomer tirucallol as two of the major products, while EtOSC6 produces taraxasterol and β-amyrin as the major products. These four compounds were also detected as the major triterpenes in the E. tirucalli latex, suggesting that EtOSC5 and EtOSC6 are the primary catalysts for the formation of E. tirucalli latex triterpene alcohols. Based on a model structure of EtOSC5 followed with site-mutagenesis experiments, the mechanism for the EtOSC5 activity was proposed. By applying state-of-the-art engineering techniques, the expression of EtOSC5 together with three other known precursor genes were chromosomally integrated into Saccharomyces cerevisiae. The resulting engineered yeast strain YS5E-1 produced 1.84 ± 0.17 mg/L of euphol in shake flasks.

中文翻译：

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在酿酒酵母中从头生物合成抗癌化合物Euphol

Euphora是一种euphane型四环三萜，主要存在于大戟属中。Euphor因其作为一种有前途的抗癌药物的巨大潜力而​​闻名。令人惊讶的是，尽管它具有多种抗肿瘤作用，但直到本研究才确定了各自的双酚生物合成基因。在我们对Euphorbia tirucalli的实验中，主要在乳胶中检测到了euphorbia tirucalli，乳胶是巴西经常用于癌症治疗的元素。来自E. tirucalli的两种乳胶特异性表达的氧化角鲨烯环化酶 (OSC) ，称为 EtOSC5 和 EtOSC6，其功能特征在于在羊毛甾醇合酶敲除酵母菌株 GIL77 中的表达。EtOSC5 生产 euphol 及其 20 S-异构体tirucallol作为两个主要产品，而EtOSC6生产taraxasterol和β-amyrin作为主要产品。这四种化合物也被检测为E. tirucalli 胶乳中的主要三萜，表明 EtOSC5 和 EtOSC6 是E. tirucalli胶乳三萜醇形成的主要催化剂。基于EtOSC5的模型结构和位点诱变实验，提出了EtOSC5活性的机制。通过应用最先进的工程技术，EtOSC5 的表达与其他三个已知的前体基因一起被染色体整合到酿酒酵母中。所产生的工程酵母菌株 YS5E-1 在摇瓶中产生 1.84 ± 0.17 mg/L 的euhol。