两种激进的 SAM 酶对于在体外生产氧杂环戊烷核苷抗病毒药物 Albucidin 是必要且充分的。
Two Radical SAM Enzymes Are Necessary and Sufficient for the In Vitro Production of the Oxetane Nucleoside Antiviral Agent Albucidin.
机构信息
Department of Chemistry, University of Texas at Austin, Austin, TX 78712, USA.
Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, University of Texas at Austin, Austin, TX 78712, USA.
出版信息
Angew Chem Int Ed Engl. 2022 Oct 17;61(42):e202210362. doi: 10.1002/anie.202210362. Epub 2022 Sep 20.
Oxetanocin A and albucidin are two oxetane natural products. While the biosynthesis of oxetanocin A has been described, less is known about albucidin. In this work, the albucidin biosynthetic gene cluster is identified in Streptomyces. Heterologous expression in a nonproducing strain demonstrates that the genes alsA and alsB are necessary and sufficient for albucidin biosynthesis confirming a previous study (Myronovskyi et al. Microorganisms 2020, 8, 237). A two-step construction of albucidin 4'-phosphate from 2'-deoxyadenosine monophosphate (2'-dAMP) is shown to be catalyzed in vitro by the cobalamin dependent radical S-adenosyl-l-methionine (SAM) enzyme AlsB, which catalyzes a ring contraction, and the radical SAM enzyme AlsA, which catalyzes elimination of a one-carbon fragment. Isotope labelling studies show that AlsB catalysis begins with stereospecific H-atom transfer of the C2'-pro-R hydrogen from 2'-dAMP to 5'-deoxyadenosine, and that the eliminated one-carbon fragment originates from C3' of 2'-dAMP.
氧杂环丁烷霉素 A 和 albucidin 是两种氧杂环丁烷天然产物。虽然已经描述了氧杂环丁烷霉素 A 的生物合成，但 albucidin 的生物合成知之甚少。在这项工作中，在链霉菌中鉴定了 albucidin 生物合成基因簇。在不产生 albucidin 的菌株中的异源表达表明，alsA 和 alsB 基因是 albucidin 生物合成所必需的，这证实了之前的一项研究（Myronovskyi 等人，Microorganisms 2020, 8, 237）。体外实验表明，来自 2'-脱氧腺苷单磷酸（2'-dAMP）的 albucidin 4'-磷酸可以由钴胺素依赖性自由基 S-腺苷甲硫氨酸（SAM）酶 AlsB 催化进行两步构建，该酶催化环缩合，以及自由基 SAM 酶 AlsA 催化一碳片段的消除。同位素标记研究表明，AlsB 催化的起始步骤是 2'-dAMP 的 C2'-pro-R 氢的立体特异性 H 原子转移到 5'-脱氧腺苷，并且消除的一碳片段来源于 2'-dAMP 的 C3'。
Zotero 插件