Kynurenine pathway has a potential to convert L-tryptophan into multiple medicinal molecules. This study aims to explore the biosynthetic potential of kynurenine pathway for the efficient production of actinocin, an antitumor precursor selected as a proof-of-concept target molecule. Kynurenine pathway is first constructed in Escherichia coli by testing various combinations of biosynthetic genes from four different organisms. Metabolic engineering strategies are next performed to improve the production by inhibiting a competing pathway, and enhancing intracellular supply of a cofactor S-adenosyl-L-methionine, and ultimately to produce actinocin from glucose. Metabolome analysis further suggests additional gene overexpression targets, which finally leads to the actinocin titer of 719 mg/L. E. coli strain engineered to produce actinocin is further successfully utilized to produce 350 mg/L of kynurenic acid, a neuroprotectant, and 1401 mg/L of 3-hydroxyanthranilic acid, an antioxidant, also from glucose. These competitive production titers demonstrate the biosynthetic potential of kynurenine pathway as a source of multiple medicinal molecules. The approach undertaken in this study can be useful for the sustainable production of molecules derived from kynurenine pathway, which are otherwise chemically synthesized.

犬尿氨酸途径具有将 L-色氨酸转化为多种药用分子的潜力。本研究旨在探索犬尿氨酸途径有效生产放线菌素的生物合成潜力，放线菌素是一种被选为概念验证靶分子的抗肿瘤前体。通过测试来自四种不同生物体的生物合成基因的各种组合，首先在大肠杆菌中构建了犬尿氨酸途径。接下来执行代谢工程策略，通过抑制竞争途径来提高产量，并增强辅因子 S-腺苷-L-甲硫氨酸的细胞内供应，并最终从葡萄糖生产放线菌素。代谢组分析进一步提示了额外的基因过表达目标，最终导致放线菌素滴度达到 719 mg/L。工程化生产放线菌素的大肠杆菌菌株还成功地利用葡萄糖生产了 350 mg/L 的犬尿酸（一种神经保护剂）和 1401 mg/L 的 3-羟基邻氨基苯甲酸（一种抗氧化剂）。这些有竞争力的生产滴度证明了犬尿氨酸途径作为多种药物分子来源的生物合成潜力。本研究中采用的方法可用于可持续生产源自犬尿氨酸途径的分子，而这些分子是通过化学合成的。