Structural basis for plant lutein biosynthesis from alpha-carotene.
Structural basis for plant lutein biosynthesis from alpha-carotene.
复制标题
从 α-胡萝卜素生物合成植物叶黄素的结构基础。
DOI：
--
复制
发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Yikun He
中科院分区：
文献类型：
--
作者：
Yikun He
两种细胞色素P450酶，CYP 97 A3和CYP 97 C1，催化α-胡萝卜素的β-和e-环的羟基化以产生叶黄素。在两个环的C-3原子处引入手性，并且反应都是亲3R-立体特异性的。我们确定了CYP 97 A3在无底物和与非天然底物的复合物形式中的晶体结构以及CYP 97 C1在去污剂结合形式中的结构。CYP 97 A3在不同状态下的结构显示了底物通道，CYP 97 C1与辛基硫代葡萄糖苷结合的结构证实了类胡萝卜素底物的结合位点。生化分析证实铁氧还蛋白-NADP+还原酶（FNR）-铁氧还蛋白对被用作氧化还原配偶体。pro-3R立体特异性的细节在视黄醇结合的CYP 97 A3结构中揭示。进一步分析表明，CYP 97 B家族与β环特异性CYP 97 A家族具有相似性。总之，我们的研究描述了叶黄素生物合成的最后步骤的分子基础。
Two cytochrome P450 enzymes, CYP97A3 and CYP97C1, catalyze hydroxylations of the β- and e-rings of α-carotene to produce lutein. Chirality is introduced at the C-3 atom of both rings, and the reactions are both pro-3R–stereospecific. We determined the crystal structures of CYP97A3 in substrate-free and complex forms with a nonnatural substrate and the structure of CYP97C1 in a detergent-bound form. The structures of CYP97A3 in different states show the substrate channel and the structure of CYP97C1 bound with octylthioglucoside confirms the binding site for the carotenoid substrate. Biochemical assays confirm that the ferredoxin-NADP + reductase (FNR)–ferredoxin pair is used as the redox partner. Details of the pro-3R stereospecificity are revealed in the retinal-bound CYP97A3 structure. Further analysis indicates that the CYP97B clan bears similarity to the β-ring–specific CYP97A clan. Overall, our research describes the molecular basis for the last steps of lutein biosynthesis.