Ribosomally synthesized and post-translationally modified peptides (RiPPs) are structurally complex natural products with diverse bioactivities. Here we report discovery of a RiPP, kintamdin, for which the structure is determined through spectroscopy, spectrometry and genomic analysis to feature a bis-thioether macrocyclic ring and a β-enamino acid residue. Biosynthetic investigation demonstrated that its pathway relies on four dedicated proteins: phosphotransferase KinD, Lyase KinC, kinase homolog KinH and flavoprotein KinI, which share low homologues to enzymes known in other RiPP biosynthesis. During the posttranslational modifications, KinCD is responsible for the formation of the characteristic dehydroamino acid residues including the β-enamino acid residue, followed by oxidative decarboxylation on the C-terminal Cys and subsequent cyclization to provide the bis-thioether ring moiety mediated by coordinated action of KinH and KinI. Finally, conserved genomic investigation allows further identification of two kintamdin-like peptides among the kin-like BGCs, suggesting the occurrence of RiPPs from actinobacteria.

核糖体合成和翻译后修饰肽 (RiPPs) 是结构复杂的天然产物，具有多种生物活性。在这里，我们报告了 RiPP，kintamdin 的发现，其结构是通过光谱学、光谱学和基因组分析确定的，以具有bis-硫醚大环和一个β-烯氨基酸残基。生物合成研究表明，其途径依赖于四种专用蛋白质：磷酸转移酶 KinD、裂解酶 KinC、激酶同源物 KinH 和黄素蛋白 KinI，它们与其他 RiPP 生物合成中已知的酶具有低同源物。在翻译后修饰过程中，KinCD 负责形成特征性脱氢氨基酸残基，包括 β-烯氨基酸残基，然后在 C 端 Cys 上进行氧化脱羧，然后环化以提供由协调作用介导的双硫醚环部分KinH 和 KinI。最后，保守的基因组研究允许进一步鉴定亲属中的两种 kintamdin 样肽-like BGCs，表明来自放线菌的 RiPPs 的发生。