Enzymatic Nitrogen Incorporation Using Hydroxylamine.
Enzymatic Nitrogen Incorporation Using Hydroxylamine.
复制标题
使用羟胺的酶促氮掺入
DOI：
10.1021/jacs.3c08053
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发表时间：
2023-09
影响因子：
15
通讯作者：
Shi-Chao Gao;Anuvab Das;Edwin Alfonzo;Kathleen M. Sicinski;Dominic Rieger;Frances H. Arnold
中科院分区：
文献类型：
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作者：
Shi-Chao Gao;Anuvab Das;Edwin Alfonzo;Kathleen M. Sicinski;Dominic Rieger;Frances H. Arnold
羟胺衍生试剂使多功能亚硝基转移反应在小分子催化和生物催化中引入含氮功能。然而，这些试剂会导致原子经济性差和化学计量有机废物。激活羟胺（NH2OH）进行硝基烯转移提供了一种低成本和可持续的胺合成途径，因为水是唯一的副产品。尽管羟胺在自然界中存在，但在生物合成中尚不知道羟胺是否用于酶促氮掺入。在这里，我们报道了一种工程血红素酶，它可以利用氯羟铵，一种廉价的商品化学品，进行亚硝基转移。砷化焦杆菌原红蛋白的定向进化产生了高效的苯乙烯氨基化和苯乙烯氨基羟基化酶。机制研究支持一种涉及限速氢原子转移的逐步自由基途径。这种前所未有的活性是对“硝基转移酶”的有益补充，并暗示未来可能发现利用羟胺进行胺化化学的天然酶。
Hydroxylamine-derived reagents have enabled versatile nitrene transfer reactions for introducing nitrogen-containing functionalities in small-molecule catalysis, as well as biocatalysis. These reagents, however, result in a poor atom economy and stoichiometric organic waste. Activating hydroxylamine (NH2OH) for nitrene transfer offers a low-cost and sustainable route to amine synthesis, since water is the sole byproduct. Despite its presence in nature, hydroxylamine is not known to be used for enzymatic nitrogen incorporation in biosynthesis. Here, we report an engineered heme enzyme that can utilize hydroxylammonium chloride, an inexpensive commodity chemical, for nitrene transfer. Directed evolution of Pyrobaculum arsenaticum protoglobin generated efficient enzymes for benzylic C-H primary amination and styrene aminohydroxylation. Mechanistic studies supported a stepwise radical pathway involving rate-limiting hydrogen atom transfer. This unprecedented activity is a useful addition to the "nitrene transferase" repertoire and hints at possible future discovery of natural enzymes that use hydroxylamine for amination chemistry.