Coronatine and related bacterial phytotoxins are mimics of the hormone jasmonyl-l-isoleucine (JA-Ile), which mediates physiologically important plant signalling pathways^1,2,3,4. Coronatine-like phytotoxins disrupt these essential pathways and have potential in the development of safer, more selective herbicides. Although the biosynthesis of coronatine has been investigated previously, the nature of the enzyme that catalyses the crucial coupling of coronafacic acid to amino acids remains unknown^1,2. Here we characterize a family of enzymes, coronafacic acid ligases (CfaLs), and resolve their structures. We found that CfaL can also produce JA-Ile, despite low similarity with the Jar1 enzyme that is responsible for ligation of JA and l-Ile in plants⁵. This suggests that Jar1 and CfaL evolved independently to catalyse similar reactions—Jar1 producing a compound essential for plant development^4,5, and the bacterial ligases producing analogues toxic to plants. We further demonstrate how CfaL enzymes can be used to synthesize a diverse array of amides, obviating the need for protecting groups. Highly selective kinetic resolutions of racemic donor or acceptor substrates were achieved, affording homochiral products. We also used structure-guided mutagenesis to engineer improved CfaL variants. Together, these results show that CfaLs can deliver a wide range of amides for agrochemical, pharmaceutical and other applications.

Coronatine 和相关的细菌植物毒素是激素茉莉酰-l-异亮氨酸 (JA-Ile) 的模拟物，它介导生理上重要的植物信号通路^1,2,3,4。冠状病毒样植物毒素会破坏这些基本途径，并有可能开发更安全、更具选择性的除草剂。尽管之前已经研究了 coronatine 的生物合成，但催化 coronafacic 酸与氨基酸关键偶联的酶的性质仍然未知^1,2。在这里，我们描述了一个酶家族，冠状酸连接酶 (CfaL)，并解析了它们的结构。我们发现 CfaL 也可以产生 JA-Ile，尽管与负责连接 JA 和l的 Jar1 酶相似性较低-Ile 在植物中⁵。这表明 Jar1 和 CfaL 独立进化以催化相似的反应——Jar1 产生植物发育所必需的化合物^4,5，而细菌连接酶产生对植物有毒的类似物。我们进一步展示了 CfaL 酶如何用于合成多种酰胺，而无需保护基团。实现了外消旋供体或受体底物的高选择性动力学拆分，提供纯手性产物。我们还使用结构引导诱变来设计改进的 CfaL 变体。总之，这些结果表明 CfaLs 可以为农化、制药和其他应用提供范围广泛的酰胺。