Bacterial Cytochrome P450 Catalyzed Post-translational Macrocyclization of Ribosomal Peptides.

Abstract

Ribosomally synthesized and post-translationally modified peptides (RiPPs) are a fascinating group of natural products that exhibit diverse structural features and bioactivities. P450-catalyzed RiPPs stand out as a unique but underexplored family. Here, we introduce a rule-based genome mining strategy that harnesses the intrinsic biosynthetic principles of RiPPs, including the co-occurrence, co-conservation, and interactions between precursors and P450s, successfully facilitating the identification of diverse P450 catalyzed RiPPs. Intensive BGC characterization revealed four new P450s, KstB, ScnB, MciB, and SgrB, that can respectively catalyze Trp-Trp-Tyr (one C-C and two C-N bonds), Tyr-Trp (C-C bond), Trp-Trp (C-N bond), and His-His (ether bond) crosslinks within three or four residues. KstB, ScnB, and MciB could accept non-native precursors, suggesting they could be promising starting templates for bioengineering to construct macrocycles. Our study highlights the potential of P450s in expanding the chemical diversity of strained macrocyclic peptides and enriching biocatalytic tools for peptide macrocyclization.