Structural basis for plant lutein biosynthesis from α-carotene
Structural basis for plant lutein biosynthesis from α-carotene
复制标题
α-胡萝卜素植物叶黄素生物合成的结构基础
DOI：
10.1073/pnas.2001806117
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发表时间：
2020-06-23
影响因子：
11.1
通讯作者：
Liu, Lin
中科院分区：
文献类型：
--
作者：
Niu, Guoqi;Guo, Qi;Liu, Lin
两种细胞色素P450酶CYP 97 A3和CYP 97 C1催化α-胡萝卜素的β-环和ε-环的羟基化以产生叶黄素。在两个环的C-3原子上引入手性，并且反应都是亲3R-立体专一性的。我们测定了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部分。pro-3R立体特异性的细节在结合于视黄醇的CYP 97 A3结构中显示.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 beta- and epsilon-rings of alpha-carotene to produce lu- tein. Chirality is introduced at the C-3 atom of both rings, and the reactions are both pro-3 R-stereospecific. We determined the crys- tal 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 part- ner. Details of the pro -3 R stereospecificity are revealed in the retinal -bound CYP97A3 structure. Further analysis indicates that the CYP97B clan bears similarity to the beta-ring -specific CYP97A clan. Overall, our research describes the molecular basis for the last steps of lutein biosynthesis.