Elucidation of the Binding Interaction between β‐Sitosterol and Lysozyme using Molecular Docking, Molecular Dynamics and Surface Plasmon Resonance Analysis

In this study, the binding behavior of β-sitosterol with lysozyme (L_ZM) was elucidated by surface plasmon resonance (SPR), computational molecular docking and molecular dynamics simulation studies. Chicken egg white lysozyme (CEWL_ZM) served as a model protein. Tri-N-acetylchitotriose (NAG₃) was used in the redocking experiments to generate precise binding location of the protein. β-sitosterol displayed a slightly better binding energy (-6.68±0.04 kcal/mol) compared to NAG₃. Further molecular dynamics simulations and MMPBSA analysis revealed that residues Glu35, Gln57-Asn59, Trp62, Ile98, Ala107 and Trp108 contribute to the binding energy. Then, 2.5 mg/mL CEWL_ZM, 1X PBS buffer (pH 7.4) as running and coupling buffers, 30 μL/min as flow rate were applied for SPR analysis. Serial β-sitosterol injections (20-150 μM) were performed through SPR sensor surface. According to SPR binding study, K_D value for β-sitosterol-CEWL_ZM binding interaction was calculated as 71.34±9.79 μM. The results could provide essential knowledge for nutrition, pharmaceutical science, and oral biology.