A comprehensive characterization of novel CYP-BM3 homolog (CYP-BA) from Bacillus aryabhattai

Abstract Functionalizing C-H bond poses one of the most significant challenges for chemists providing them with very few substrate-specific synthetic routes. Despite being incredibly plastic in their enzymatic ability, they are confined with deficient enzymatic action and limited explicitness of the substrates. In this study, we have endeavored to characterize novel cytochrome P450 from Bacillus aryabhattai (CYP-BA), a homolog of CYP P450-BM3, by taking interdisciplinary approaches. We conducted structure and sequence comparison to understand the conservation pattern for active site residues, conserved fold, evolutionary relationships among others. Molecular dynamics simulations were performed to understand the dynamic nature and interaction with the substrates. CYP-BA was successfully cloned, purified, and characterized. The enzyme's stability towards various physicochemical parameters was evaluated by UV-Visible spectroscopy and circular dichroism (CD) spectroscopy. Various saturated fatty acids being the natural cytochrome P450 substrates were evaluated as catalytic efficiency of substrate oxidation by CYP-BA. The binding affinity of these natural substrates was monitored against CYP-BA by isothermal titration calorimetry (ITC). The catalytic performance of CYP-BA was satisfactory enough to proceed to the next step, that is, engineering to expand the substrate range to include polycyclic aromatic hydrocarbons (PAH). This is the first evidence of cloning, purifying and characterizing a novel homolog of CYP-BM3 to enable a better understanding of this novel biocatalyst and to provide a platform towards expanding its catalytic process through enzyme engineering.