Genetic dissection of persiathiacin biosynthesis defines hierarchical P450 oxidations and reveals a more potent antitubercular intermediate

Abstract

Thiopeptides are ribosomally synthesized and post-translationally modified peptides (RiPPs) that form complex bioactive scaffolds through extensive enzymatic tailoring. The polyglycosylated thiopeptides persiathiacins, exhibit potent activity against multidrug-resistant Mycobacterium tuberculosis (Mtb) and methicillin-resistant Staphylococcus aureus (MRSA). The persiathiacin biosynthetic gene cluster encodes six cytochrome P450 (CYP) enzymes, but the logic of their oxidative modifications was unknown. Here, we establish a protoplast-based genetic system for Actinokineospora and systematically assign functions to all P450s. We demonstrate that PerX hydroxylates the central thiazole, PerV installs the third indole–core crosslink required for macrocyclization, and PerT, not PerU, catalyses indole N-hydroxylation. Combined gene inactivation and metabolite profiling reveal a hierarchical enzymatic sequence leading to the mature scaffold prior to sugar installation. Notably, the intermediate accumulating in the ΩperX mutant exhibits enhanced anti-M. tuberculosis potency compared to persiathiacin A (IC50 = 0.07 vs 1.5 µg mL−1). These results define the enzymatic logic and temporal organization of persiathiacin biosynthesis, providing a conceptual framework for rational diversification of complex thiopeptide natural products.