State Key Laboratory of Pharmaceutical Biotechnology, Chemistry and Biomedicine Innovation Centre, Institute of Artificial Intelligence Biomedicine, School of Life Sciences, Nanjing University, Nanjing, 210023, China.
State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, Chemistry and Biomedicine Innovation Centre, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China.
Nat Commun. 2022 Aug 3;13(1):4499. doi: 10.1038/s41467-022-32088-4.
Macrocyclization is an important process that affords morphed scaffold in biosynthesis of bioactive natural products. Nature has adapted diverse biosynthetic strategies to form macrocycles. In this work, we report the identification and characterization of a small enzyme AvmM that can catalyze the construction of a 16-membered macrocyclic ring in the biosynthesis of alchivemycin A (1). We show through in vivo gene deletion, in vitro biochemical assay and isotope labelling experiments that AvmM catalyzes tandem dehydration and Michael-type addition to generate the core scaffold of 1. Mechanistic studies by crystallography, DFT calculations and MD simulations of AvmM reveal that the reactions are achieved with assistance from the special tenuazonic acid like moiety of substrate. Our results thus uncover an uncharacterized macrocyclization strategy in natural product biosynthesis.
大环化是生物合成具有生物活性天然产物的重要过程，它提供了形态变化的支架。自然界已经适应了多种生物合成策略来形成大环。在这项工作中，我们报告了一种小酶 AvmM 的鉴定和表征，它可以在 alchivemycin A（1）的生物合成中催化构建 16 元大环环。我们通过体内基因缺失、体外生化测定和同位素标记实验表明，AvmM 催化串联脱水和迈克尔型加成反应生成 1 的核心支架。通过 AvmM 的晶体学、DFT 计算和 MD 模拟的机制研究表明，这些反应是在底物的特殊替考拉宁样部分的辅助下完成的。因此，我们的研究结果揭示了天然产物生物合成中一种未被描述的大环化策略。
