Overcoming methicillin resistance by methicillin-resistant Staphylococcus aureus: Computational evaluation of napthyridine and oxadiazoles compounds for potential dual inhibition of PBP-2a and FemA proteins

The treatment of the various infections caused by Staphylococcus aureus has become challenging due to the evolving resistance against current therapeutics. In this study, the potentials of napthyridine and oxadiazole derivatives to serve as dual inhibitors of penicillin-binding protein 2a (PBP-2a) and FemA protein, which are crucial to resistance to methicillin-based drugs by S. aureus, were evaluated using molecular modeling techniques. Seventy-two compounds were subjected to molecular docking against the proteins, and the hit compounds were subjected to drug-likeness evaluation and in silico pharmacokinetics prediction. The compounds with good safety profiles were subjected to a 250-ns molecular dynamics (MD) simulation and other relevant analyses based on the MD trajectories. Five hit compounds were selected based on their high affinity for the targets as evidenced by their docking scores ranging from -8.6 to -10.1 kcal/mol for PBP-2a and -9.6 to -9.9 kcal/mol for FemA. These compounds also passed Lipinski's rule of five evaluation with no violation and possessed high human intestinal absorption potential, showcasing their potential as orally administered therapeutic agents. However, three of the compounds were potential mutagens. MD simulation revealed that the final two compounds maintained stable interactions with the target proteins over 250 ns, with minimal deviations and fluctuations. Hydrogen bond stability and energy decomposition analysis further confirmed the strong binding affinity of the hit compounds compared to the control drug, methicillin. Conclusively, the compounds with the CID "135964525" and "44130718" are worthy of further experimental validation in the development of potential inhibitors of PBP-2a and FemA.