Structural and Mechanistic Insights into Oxidative Biaryl Coupling to form Arylomycin Core by an Engineered CYP450

Arylomycin, a potent antibiotic targeting bacterial signal peptidases, is difficult to synthesize experimentally due to poor to moderate yields and formation of mixture of compounds, Therefore, there is a need to focus on some greener catalyst. Enzymes are increasingly recognised as green catalysts for synthesis for new-to-nature reactions due to their chemo-selectivity and mild operating conditions, aligning with the principles of green chemistry. Cytochrome P450 enzymes, a group of heme-containing proteins, emerged as promising catalysts due to their ability to facilitate diverse oxidative transformations. Here, we discuss an engineered Cytochrome P450 enzyme from Streptomyces sp. for the synthesis of arylomycin core. Through molecular dynamics simulations, we investigated the impact of specific mutations: glycine101 to alanine mutation, which facilitates biaryl coupling by subtly pushing the substrate and glutamine306 to histidine mutation, exhibiting stable pi-pi interactions with substrate, which helps the two phenol rings of substrate to stay close to each other to undergo C-C coupling. Quantum mechanics/molecular mechanics (QM/MM) calculations investigated that variant 2 favours biradical mechanism of C-C bond formation over hydroxylation.