Fraxetin, which is a simple coumarin, is a phytochemical present in medicinal plants, such as Fraxinus rhynchophylla, and Cortex Fraxini. In plants, it serves as a controller of iron homeostasis. The health-enhancing activities of fraxetin, such as anticancer, neuroprotective and antibacterial activities, are known. Scopoletin 8-hydroxylase (S8H) is a key enzyme involved in the synthesis of fraxetin from scopoletin. Scopoletin can be synthesized either from esculetin by O-methylation or from ferulic acid by feruloyl CoA 6′-hydroxylase (F6′H) and 4-coumaric acid CoA ligase (4CL). To enable fraxetin synthesis, the fraxetin biosynthesis pathway was introduced into Escherichia coli. Three distinct routes, from ferulic acid, esculetin, and scopoletin, were designed for the synthesis of fraxetin. In the first approach, E. coli strain harboring S8H was used and found to synthesize 84.8 μM fraxetin from 100 μM scopoletin. Two E. coli strains were used for the other two approaches because these approaches required at least two enzymatic reactions. Through this approach, 41.4 μM fraxetin was synthesized from 100 μM esculetin, while 33.3 μM fraxetin was synthesized from 100 μM ferulic acid.

中文翻译：

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使用工程大肠杆菌从三种不同的底物生物合成佛拉西汀

Fraxetin是一种简单的香豆素，是药用植物中的一种植物化学成分，例如Fraxinus rhynchophylla和Cortex Fraxini。在植物中，它是铁稳态的控制者。已知法拉西汀具有增强健康的活性，例如抗癌，神经保护和抗菌活性。大麦草碱8-羟化酶（S8H）是参与从大麦草碱合成弗拉西汀的关键酶。麦考菌碱可以通过欧司他汀通过O-甲基化合成，也可以通过阿魏酸通过阿魏酰CoA 6'-羟化酶（F6'H）和4-香豆酸CoA连接酶（4CL）合成。为了实现弗拉西汀的合成，将弗拉西汀的生物合成途径引入了大肠杆菌。设计了来自阿魏酸，七叶皂素和大麦草碱的三种截然不同的路线来合成法沙汀。在第一种方法中，E。使用了带有S8H的大肠杆菌菌株，发现该菌株可从100μMscopoletin合成84.8μMfraxetin。另两种方法使用了两种大肠杆菌菌株，因为这些方法需要至少两种酶促反应。通过这种方法，从100μM七叶皂甙合成41.4μMfraxetin，而从100μM阿魏酸合成33.3μMfraxetin。