In Silico molecular insights into CYP3A-mediated monensin detoxification across species

Abstract

Monensin is an ionophore antibiotic widely used in veterinary medicine, known for its marked species-specific toxicity with Equus caballus being the most sensitive species, Sus scrofa partially tolerant, while Gallus gallus is the most tolerant. It has been reported that such variability may depends on differences in CYP3A-mediated metabolism, particularly related to the O-demethylation reaction, which plays a key role in monensin detoxification. In this study, we applied a 3D modelling-based pipeline, including molecular docking, dynamics simulations and machine learning driven post-processing analysis, to investigate the interaction of monensin with CYP3A isoforms from chickens, pigs, and horses. The data collected unveiled interspecies and isoform-specific differences in both monensin binding and stability within CYP3A isoforms, providing a molecular basis for the species-related toxicity profile and O-demethylation efficiency previously described. These results were also corroborated by differences in terms of amino acid residues shaping the tested CYP3A catalytic sites. These findings provide mechanistic insights into interspecies variability regarding monensin detoxification and highlight the impact of in silico approaches on mechanistic toxicology studies related to risk assessment.