P450 Biarylitide Synthase ShyB Catalyzes the Cross-Link Between His-C2 and Tyr-O4 on the Precursor Peptide

Biarylitides are a new class of ribosomally synthesized and post-translationally modified peptides (RiPPs) with the unique feature of biaryl C-C, C-N, or C-O cross-links installed by P450 biarylitide synthases (P450s). Here, we manually identified 435 homologous P450s linked to putative biarylitide precursor peptides, which is the most extensive list of biarylitide precursor peptide so far reported. Through in vivo functional studies in E. coli, the newly identified enzyme ShyB from Streptomyces clavuligerus F613-1 was found to catalyze formation of a cross-link between His-C2 and Tyr-O4 on the precursor peptide ShyA. This is the first report of an enzyme that can catalyze such cross-linking in RiPPs.