Binding Affinity and Interaction Mechanism of Chlorhexidine with Lysozyme: Insights from Surface Plasmon Resonance, Molecular Docking, and Molecular Dynamics Simulations

This study investigates the binding affinity and interaction mechanism of chlorhexidine (CHX), a commonly used antimicrobial agent, with lysozyme (LZM), a crucial salivary enzyme in the oral cavity. Chicken egg white lysozyme (CEWLZM) was used as a model LZM. Tri-N-acetylchitotriose (NAG3) was applied in redocking analysis to determine the exact binding sites of the CEWLZM. The study elucidates how CHX interacts with LZM at the molecular level, employing surface plasmon resonance (SPR), molecular docking, and molecular dynamics (MD) simulations. The SPR analysis revealed that CHX as an exogenous substance showed significant affinity for CEWLZM, with an equilibrium dissociation constant of 43.39 +/- 2.07 mu M. Molecular docking and MD simulations further demonstrated that CHX primarily binds at the active site of CEWLZM, stabilizing the complex via hydrophobic interactions and hydrogen bonding. These findings suggest that CHX's presence in the oral cavity could impact lysozyme's natural antimicrobial functions, potentially influencing oral health. This research provides insight into optimizing CHX-containing products, balancing antimicrobial efficacy with minimal interference with host defense enzymes, which may enhance the safety and effectiveness of CHX in oral care applications.