The kynurenine pathway, named after its nonproteinogenic amino acid precursor l-kynurenine, is responsible for the de novo biosynthesis of nicotinamide adenine dinucleotide (NAD+) in eukaryotes. Oxo-(2-aminophenyl) and quinoline molecules downstream from l-kynurenine also serve as antagonists of several receptors of the central nervous system in mammals. In this study, we engineered new biosynthetic routes in yeast Saccharomyces cerevisiae to produce a suite of l-kynurenine-derived natural products. Overexpression of Homo sapiens l-tryptophan 2,3-dioxygenase (HsTDO2) in S. cerevisiae led to a marked increase in the production of l-kynurenine and downstream metabolites. Using this background, new branch points to the kynurenine pathway were added through the incorporation of a Psilocybe cubensis noncanonical L-aromatic amino acid decarboxylase (PcncAAAD) capable of catalyzing both decarboxylation and decarboxylation-dependent oxidative-deamination reactions of l-kynurenine and 3-hydroxy-l-kynurenine to yield their corresponding monoamines, aldehydes, and downstream nonenzymatically cyclized quinolines. The PcncAAAD-catalyzed decarboxylation products, kynuramine and 3-hydroxykynuramine, could further be converted to quinoline scaffolds through the addition of H. sapiens monoamine oxidase A (HsMAO-A). Finally, by incorporating upstream regiospecific l-tryptophan halogenases into the engineering scheme, we produced a number of halogenated oxo-(2-aminophenyl) and quinoline compounds. This work illustrates a synthetic biology approach to expand primary metabolic pathways in the production of novel natural-product-like scaffolds amenable for downstream functionalization.

中文翻译：

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设计Kynurenine途径的新分支，以在酵母中生产Oxo-（2-氨基苯基）和喹啉支架。

犬尿氨酸途径以其非蛋白原性氨基酸前体1-犬尿氨酸命名，负责真核生物中烟酰胺腺嘌呤二核苷酸（NAD +）的从头生物合成。l-犬尿氨酸下游的氧-（2-氨基苯基）和喹啉分子还可以充当哺乳动物中枢神经系统几种受体的拮抗剂。在这项研究中，我们设计了酿酒酵母中的新生物合成途径，以生产一整套l-犬尿氨酸衍生的天然产物。在酿酒酵母中智人L-色氨酸2,3-二加氧酶（HsTDO2）的过表达导致L-犬尿氨酸和下游代谢产物的产量显着增加。使用此背景，通过掺入能够催化l-犬尿氨酸和3-羟基-1-l的脱羧和依赖脱羧反应的氧化-脱氨反应的Psilocybe cubensis非规范L-芳族氨基酸脱羧酶，添加到犬尿氨酸途径的新分支点。犬尿氨酸产生其相应的单胺，醛和下游非酶环化喹啉。PcncAAAD催化的脱羧产物Kynuramine和3-hydroxykynuramine可以通过添加人单链梭菌单胺氧化酶A（HsMAO-A）进一步转化为喹啉支架。最后，通过将上游区域特异的L-色氨酸卤化酶整合到工程方案中，我们生产了许多卤代氧代（2-氨基苯基）和喹啉化合物。