Compartmentalized biosynthesis of mycophenolic acid.
Compartmentalized biosynthesis of mycophenolic acid.
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麦考酚酸的区室化生物合成。
DOI：
10.1073/pnas.1821932116
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发表时间：
2019
影响因子：
11.1
通讯作者：
Li Shengying
中科院分区：
文献类型：
--
作者：
Zhang Wei;Du Lei;Qu Zepeng;Zhang Xingwang;Li Fengwei;Li Zhong;Qi Feifei;Wang Xiao;Jiang Yuanyuan;Men Ping;Sun Jingran;Cao Shaona;Geng Ce;Qi Fengxia;Wan Xiaobo;Liu Changning;Li Shengying
丝状真菌中的霉酚酸是第一个被分离和结晶的天然产物抗生素，也是治疗器官移植和自身免疫性疾病的一线免疫抑制药物。然而，这种古老而重要的分子的一些关键生物合成机制仍不清楚。在这里，我们阐明了MPA的生物合成途径，其特点是以靶向基因失活为基础的生物合成和β氧化分解代谢机制之间的独特合作，异源表达宿主中的喂养实验，酶功能表征和动力学分析，以及蛋白质亚细胞定位的微观观察。除了确定加氧酶MpaB‘是导致法尼基侧链氧化断裂的关键酶外，我们还揭示了MPA生物合成酶有趣的区划模式，包括胞质聚酮合成酶MPAC’Ando-甲基转移酶MpaG‘，高尔基体相关的戊烯基转移酶MPAA’，内质网结合的加氧酶MpaB‘和P450-水解酶融合酶MpaDE’，以及过氧体酰基辅酶A(CoA)水解酶MpaH‘。整个过程由这些分隔的酶和过氧体β氧化机制巧妙地融合在一起。除了描述MPA生物合成步骤中剩余的突出步骤外，我们的研究还强调了在天然产品生物合成中考虑亚细胞环境和更广泛的细胞代谢的重要性。
Mycophenolic acid (MPA) from filamentous fungi is the first natural product antibiotic to be isolated and crystallized, and a first-line immunosuppressive drug for organ transplantations and autoimmune diseases. However, some key biosynthetic mechanisms of such an old and important molecule have remained unclear. Here, we elucidate the MPA biosynthetic pathway that features both compartmentalized enzymatic steps and unique cooperation between biosynthetic and β-oxidation catabolism machineries based on targeted gene inactivation, feeding experiments in heterologous expression hosts, enzyme functional characterization and kinetic analysis, and microscopic observation of protein subcellular localization. Besides identification of the oxygenase MpaB′ as the long-sought key enzyme responsible for the oxidative cleavage of the farnesyl side chain, we reveal the intriguing pattern of compartmentalization for the MPA biosynthetic enzymes, including the cytosolic polyketide synthase MpaC′ andO-methyltransferase MpaG′, the Golgi apparatus-associated prenyltransferase MpaA′, the endoplasmic reticulum-bound oxygenase MpaB′ and P450-hydrolase fusion enzyme MpaDE′, and the peroxisomal acyl-coenzyme A (CoA) hydrolase MpaH′. The whole pathway is elegantly comediated by these compartmentalized enzymes, together with the peroxisomal β-oxidation machinery. Beyond characterizing the remaining outstanding steps of the MPA biosynthetic steps, our study highlights the importance of considering subcellular contexts and the broader cellular metabolism in natural product biosynthesis.