Department of Chemistry, Texas A&M University , College Station, Texas 77842, United States.
J Am Chem Soc. 2017 Aug 16;139(32):10952-10955. doi: 10.1021/jacs.7b04209. Epub 2017 Aug 3.
Aminofutalosine synthase (MqnE) is a radical SAM enzyme involved in the menaquinone biosynthetic pathway. In this communication, we propose a novel mechanism for this reaction involving the addition of the adenosyl radical to the substrate double bond to form a captodative radical followed by rearrangement and decarboxylation to form an aryl radical anion which is then oxidized by the [4Fe-4S] cluster. Consistent with this proposal, we describe the trapping of the captodative radical and the aryl radical anion using radical triggered C-Br fragmentation reactions. We also describe the trapping of the captodative radical by replacing the vinylic carboxylic acid with an amide.
氨基糠醛缩氨酸合酶（MqnE）是一种参与维生素 K 生物合成途径的自由基 SAM 酶。在本通讯中，我们提出了一种涉及将腺嘌呤基自由基添加到底物双键以形成亲核性自由基的新反应机制，随后进行重排和脱羧以形成芳基自由基阴离子，然后由 [4Fe-4S] 簇氧化。与该建议一致，我们描述了使用自由基引发的 C-Br 断裂反应捕获亲核性自由基和芳基自由基阴离子。我们还通过用酰胺取代乙烯基羧酸来描述亲核性自由基的捕获。
