Zhao Yong, Liang Feiyan, Xie Yuman, Duan Yao-Tao, Andeadelli Aggeliki, Pateraki Irini, Makris Antonios M, Pomorski Thomas G, Staerk Dan, Kampranis Sotirios C
Biochemical Engineering Group, Plant Biochemistry Section, Department of Plant and Environment Sciences, Faculty of Science, University of Copenhagen, Thorvaldsensvej 40, Frederiksberg C 1871, Denmark.
Institute of Applied Biosciences, Centre for Research & Technology, Hellas (CERTH), Thessaloniki 57001, Greece.
J Am Chem Soc. 2024 Jan 10;146(1):801-810. doi: 10.1021/jacs.3c10864. Epub 2023 Dec 21.
Taxol is a potent drug used in various cancer treatments. Its complex structure has prompted extensive research into its biosynthesis. However, certain critical steps, such as the formation of the oxetane ring, which is essential for its activity, have remained unclear. Previous proposals suggested that oxetane formation follows the acetylation of taxadien-5α-ol. Here, we proposed that the oxetane ring is formed by cytochrome P450-mediated oxidation events that occur prior to C5 acetylation. To test this hypothesis, we analyzed the genomic and transcriptomic information for species to identify cytochrome P450 candidates and employed two independent systems, yeast () and plant (), for their characterization. We revealed that a single enzyme, CYP725A4, catalyzes two successive epoxidation events, leading to the formation of the oxetane ring. We further showed that both taxa-4(5)-11(12)-diene (endotaxadiene) and taxa-4(20)-11(12)-diene (exotaxadiene) are precursors to the key intermediate, taxologenic oxetane, indicating the potential existence of multiple routes in the Taxol pathway. Thus, we unveiled a long-elusive step in Taxol biosynthesis.
紫杉醇是一种用于多种癌症治疗的强效药物。其复杂的结构促使人们对其生物合成进行了广泛研究。然而，某些关键步骤，如对其活性至关重要的氧杂环丁烷环的形成，仍不清楚。先前的推测表明，氧杂环丁烷的形成是在紫杉二烯-5α-醇乙酰化之后。在这里，我们提出氧杂环丁烷环是由细胞色素P450介导的氧化事件形成的，这些事件发生在C5乙酰化之前。为了验证这一假设，我们分析了多个物种的基因组和转录组信息，以确定细胞色素P450候选基因，并采用酵母（）和植物（）这两个独立的系统对其进行表征。我们发现，一种单一的酶CYP725A4催化两个连续的环氧化事件，导致氧杂环丁烷环的形成。我们进一步表明，紫杉-4(5)-11(12)-二烯（内紫杉醇二烯）和紫杉-4(20)-11(12)-二烯（外紫杉醇二烯）都是关键中间体——产紫杉烷氧杂环丁烷的前体，这表明紫杉醇生物合成途径中可能存在多种途径。因此，我们揭示了紫杉醇生物合成中一个长期难以捉摸的步骤。
