A different function for a member of an ancient and highly conserved cytochrome P450 family: From essential sterols to plant defense
A different function for a member of an ancient and highly conserved cytochrome P450 family: From essential sterols to plant defense
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DOI：
10.1073/pnas.0607849103
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发表时间：
2006-12-05
影响因子：
11.1
通讯作者：
Osbourn, Anne
中科院分区：
文献类型：
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作者：
Qi, Xiaoquan;Bakht, Saleha;Osbourn, Anne
CYP 51甾醇脱甲基酶是唯一在动物、真菌和植物界具有保守功能的细胞色素P450酶（在必需甾醇的合成中）。这些高度保守的酶是降胆固醇药物、抗真菌药物和抗肿瘤药物的重要靶点。除草剂和除草剂被认为是细胞色素P450家族中最古老的成员。在这里，我们提出了一个报告的CYP 51酶，已获得不同的功能。我们表明，植物酶AsCYP 51 H10是必需的甾醇合成的必需品，并已被招募的抗菌化合物（燕麦），赋予燕麦抗病性的生产。AsCyp 51 H10基因与Sad 2同义，Sad 2是我们先前通过突变定义为燕麦新合成所需的基因。在早期的工作中，我们发现，Sad 1，基因编码的第一个致力于酶燕麦素途径（β-香树脂素合成酶），已经出现了重复和分歧的环阿屯醇脱氢酶样基因。这些数据共同表明了固醇和燕麦新途径之间的密切进化联系。Sad 1和Sad 2位于彼此之间的70 kb内，并且在燕麦素积累部位的根尖的表皮细胞中特异性表达。这些发现提出了关于这种专门的防御相关代谢途径的组成部分的招募，共同进化和调节的有趣问题。
CYP51 sterol demethylases are the only cytochrome P450 enzymes with a conserved function across the animal, fungal, and plant kingdoms (in the synthesis of essential sterols). These highly conserve enzymes, which are important targets for cholesterol-lowering drugs, antifungal a. gents, and herbicides, are regarded as the most ancient member cytochrome P450 family. Here we present a report of a CYP51 enzyme that has acquired a different function. We show that the plant enzyme AsCYP51H10 is dispensable for synthesis of essential sterols and has been recruited for the production of antimicrobial compounds (avenacins) that confer disease resistance in oats. The AsCyp51H10 gene is synonymous with Sad2, a gene that we previously had defined by mutation as being required for avenacin synthesis. In earlier work, we showed that Sad1, the gene encoding the first committed enzyme in the avenacin pathway (beta-amyrin synthase), had arisen by duplication and divergence of a cycloartenol synthase-like gene. Together these data indicate an intimate evolutionary connection between the sterol and avenacin pathways. Sad1 and Sad2 lie within 70 kb of each * other and are expressed specifically in the epidermal cells of,the root tip, the site of accumulation of avenacins. These findings raise, intriguing questions about the recruitment, coevolution, and regulation of the components of this specialized defense-related metabolic pathway.