Taxol biosynthesis:: Molecular cloning and of a cytochrome p450 characterization taxoid 7β-hydroxylase
Taxol biosynthesis:: Molecular cloning and of a cytochrome p450 characterization taxoid 7β-hydroxylase
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DOI：
10.1016/j.chembiol.2004.02.025
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发表时间：
2004-05-01
影响因子：
--
通讯作者：
Croteau, R
中科院分区：
文献类型：
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作者：
Chau, M;Jennewein, S;Croteau, R
紫杉类抗癌药物紫杉醇的生物合成涉及八个细胞色素P450介导的氧化和四个辅酶A依赖的酰化的二萜类核心。从红豆杉细胞cDNA文库中获得了一个细胞色素P450基因家族，并以紫杉醇（taxa-4（20），11（12）-dien-5 alpha，9 alpha，10 beta，13 alpha-tetraol tetraacetate）为底物进行了功能性表达和筛选。一个克隆将这种底物转化为氧化衍生物，被鉴定为7 β-羟基紫杉醇。该7 β-羟化酶的结构和性质与其他紫杉烷羟化酶相似。动力学和结合试验表明7 β-羟化酶对多氧和酰化紫杉烷底物的选择性，这一观察结果与紫杉醇生物合成途径中心部分的这种酶的操作一致。虽然紫杉醇的7 β-羟基对于抗有丝分裂活性不是必需的，但是该官能团提供了制备紫杉烷衍生物的方便方法。
Biosynthesis of the anticancer drug Taxol in yew species involves eight cytochrome P450-mediated oxygenations and four coenzyme A-dependent acylations of the diterpenoid core. A family of cytochrome P450 genes, obtained from a yew cell cDNA library, were functionally expressed and screened with taxusin (taxa-4(20),11(12)-dien-5alpha,9alpha,10beta,13alpha-tetraol tetraacetate) as a surrogate substrate. One clone converted this substrate to an oxygenated derivative that was identified as 7beta-hydroxytaxusin. The structure and properties of this 7beta-hydroxylase are similar to those of other taxoid hydroxylases. Kinetic and binding assays indicated selectivity of the 7beta-hydroxylase for polyoxygenated and acylated taxoid substrates, an observation consistent with the operation of this enzyme in the central portion of the Taxol biosynthetic pathway. Although the 7beta-hydroxyl of Taxol is not essential for antimitotic activity, this functional group provides a convenient means for preparing taxoid derivatives.