Cytochrome P450 OxyBtei Catalyzes the First Phenolic Coupling Step in Teicoplanin Biosynthesis

Bacterial cytochrome P450s form a remarkable clade of the P450 superfamily of oxidative hemoproteins, and are often involved in the biosynthesis of complex natural products. Those in a subgroup known as “Oxy enzymes” play a crucial role in the biosynthesis of glycopeptide antibiotics, including vancomycin and teicoplanin. The Oxy enzymes catalyze crosslinking of aromatic residues in the non‐ribosomal antibiotic precursor peptide while it remains bound to the non‐ribosomal peptide synthetase (NRPS); this crosslinking secures the three‐dimensional structure of the glycopeptide, crucial for antibiotic activity. We have characterized OxyBtei, the first of the Oxy enzymes in teicoplanin biosynthesis. Our results reveal that OxyBtei possesses a structure similar to those of other Oxy proteins and is active in crosslinking NRPS‐bound peptide substrates. However, OxyBtei displays a significantly altered activity spectrum against peptide substrates compared to its well‐studied vancomycin homologue. The characterization of OxyBtei, the first cytochrome P450 involved in peptide crosslinking from teicoplanin biosynthesis, has shown OxyBtei to have a dramatically higher selectivity for carrier‐protein‐bound peptides compared to the vancomycin homologue, despite the high degree of structural and sequence similarity.