Cytochrome P450 and O-methyltransferase catalyze the final steps in the biosynthesis of the anti-addictive alkaloid ibogaine from Tabernanthe iboga.
Cytochrome P450 and O-methyltransferase catalyze the final steps in the biosynthesis of the anti-addictive alkaloid ibogaine from Tabernanthe iboga.
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DOI：
10.1074/jbc.ra118.004060
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发表时间：
2018-09-07
期刊：
影响因子：
--
通讯作者：
O'Connor SE
中科院分区：
文献类型：
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作者：
Farrow SC;Kamileen MO;Meades J;Ameyaw B;Xiao Y;O'Connor SE
单萜吲哚生物碱是一类结构多样的代谢产物，仅分布于龙胆目的少数植物科。Tabernanthe iboga或iboga（夹竹桃科）原产于赤道非洲西部，几个世纪以来一直用于传统医学。霍华德Lotsof被认为是通过他偶然发现iboga可以缓解阿片类药物戒断症状而使iboga引起西方医学的注意。自从这一观察以来，iboga已经被研究用于成瘾的一般管理。我们有兴趣阐明伊波替尼的生物合成，以了解伊波替尼的独特反应步骤。此外，由于伊博替尼目前来源于植物材料，这些研究可能有助于通过合成生物学方法改善伊博替尼供应链。在这里，我们使用下一代测序来生成第一个iboga转录组，并利用同源性指导的基因发现来鉴定iboga生物合成中的倒数第二个羟化酶和最终的O-甲基转移酶步骤，本文称为ibogamine 10-羟化酶（I10 H）和noriboga-10-O-甲基转移酶（N10 OMT）。在酿酒酵母（I10 H）或大肠杆菌（N10 OMT）中的异源表达和与推定的前体一起孵育，沿着HPLC-MS分析，证实了两种酶的预测活性。此外，在积累伊波加因的植物组织中检测到它们的转录物的高表达水平。这些发现加上我们公开的iboga转录组将有助于更多的基因发现工作，并可能导致全球iboga供应链的稳定和iboga作为成瘾治疗的发展。
Monoterpenoid indole alkaloids are a large (∼3000 members) and structurally diverse class of metabolites restricted to a limited number of plant families in the order Gentianales. Tabernanthe iboga or iboga (Apocynaceae) is native to western equatorial Africa and has been used in traditional medicine for centuries. Howard Lotsof is credited with bringing iboga to the attention of Western medicine through his accidental discovery that iboga can alleviate opioid withdrawal symptoms. Since this observation, iboga has been investigated for its use in the general management of addiction. We were interested in elucidating ibogaine biosynthesis to understand the unique reaction steps en route to ibogaine. Furthermore, because ibogaine is currently sourced from plant material, these studies may help improve the ibogaine supply chain through synthetic biology approaches. Here, we used next-generation sequencing to generate the first iboga transcriptome and leveraged homology-guided gene discovery to identify the penultimate hydroxylase and final O-methyltransferase steps in ibogaine biosynthesis, herein named ibogamine 10-hydroxylase (I10H) and noribogaine-10-O-methyltransferase (N10OMT). Heterologous expression in Saccharomyces cerevisiae (I10H) or Escherichia coli (N10OMT) and incubation with putative precursors, along with HPLC–MS analysis, confirmed the predicted activities of both enzymes. Moreover, high expression levels of their transcripts were detected in ibogaine-accumulating plant tissues. These discoveries coupled with our publicly available iboga transcriptome will contribute to additional gene discovery efforts and could lead to the stabilization of the global ibogaine supply chain and to the development of ibogaine as a treatment for addiction.