Discovery and Biosynthesis of Cihunamides, Macrocyclic Antibacterial RiPPs with a Unique C−N Linkage Formed by CYP450 Catalysis
Joon Soo An, Hyunbin Lee, Hyun‐Gyu Kim, Seungyeon Woo, Hyunsung Nam, Jayho Lee, Ji Yun Lee, Sang‐Jip Nam, Sang Kook Lee, Ki‐Bong Oh, Seokhee Kim, Dong‐Chan Oh
Abstract
N NMR, MS, and chemical derivatization; they contain a tetrapeptide core composed of WNIW, cyclized by a unique C-N linkage between two Trp units. Genome mining of the producer strain revealed two biosynthetic genes encoding a cytochrome P450 enzyme and a precursor peptide. Heterologous co-expression of the core genes demonstrated the biosynthesis of cihunamides through P450-mediated oxidative Trp-Trp cross-linking. Further bioinformatic analysis uncovered 252 homologous gene clusters, including that of tryptorubins, which possess a distinct Trp-Trp linkage. Cihunamides do not display the non-canonical atropisomerism shown in tryptorubins, which are the founding members of the "atropitide" family. Therefore, we propose to use a new RiPP family name, "bitryptides", for cihunamides, tryptorubins, and their congeners, wherein the Trp-Trp linkages define the structural class rather than non-canonical atropisomerism.