Structural alterations and inhibition of lysozyme activity upon binding interaction with rotenone: Insights from spectroscopic investigations and molecular dynamics simulation

The pervasive employment of pesticides such as rotenone on a global scale represents a substantial hazard to human health through direct exposure. Therefore, exploring the interactions between such compounds and body macromolecules such as proteins is crucial in comprehending the underlying mechanisms of their detrimental effects. The present study aims to delve into the molecular interaction between rotenone and lysozyme by employing spectroscopic techniques along with Molecular dynamics (MD) simulation in mimicked physiological conditions. The binding interaction resulted in a fluorescence quenching characterized by both dynamic and static mechanisms, with static quenching playing a prominent role in governing this phenomenon. The analysis of thermodynamic parameters indicated that hydrophobic interactions primarily governed the spontaneous bonding process. FT-IR and circular dichroism findings revealed structural alternations of lysozyme upon complexation with rotenone. Also, complexation with rotenone declined the biological activity of lysozyme, thus rotenone could be considered an enzyme inhibitor. Further, the binding interaction substantially decreased the thermal stability of lysozyme. Molecular docking studies showed the binding location and the key residues interacting with rotenone. The findings of the spectroscopic investigations were confirmed and accurately supported by MD simulation studies.