ROLE OF ELECTROSTATIC INTERACTIONS IN LYSOZYME ADSORPTION ONTO CHARGED PLANAR SURFACE

The adsorption of proteins onto surfaces plays an important role in numerous biological processes. Since proteins contain a significant number of ionizable groups, electrostatic interactions are a major factor in these systems, as evidenced by the dependence of adsorption on the ionic strength and pH of the solution. Therefore, understanding how electrostatic interactions and charge regulation modulate protein–surface interactions is highly valuable. In this study, we investigate the impact of electrostatic interactions between egg-white lysozyme (PDB ID: 3WUN) and a homogeneously charged planar surface on protein adsorption and orientation. The surface potential is calculated using the Poisson–Boltzmann equation, and surface charge densities at different pH values are derived from experimental data on silica nanoparticles. The protein was modeled according to the structure-based model (SBM), with a screened Coulomb potential accounting for residue–residue electrostatic interactions. Using Monte Carlo Metropolis simulations, we examine the pH-dependent adsorption profile to evaluate the role of charge regulation and its effect on adsorption orientation. Additionally, comparisons are made with protein adsorption inside a cylindrical pore to explore the influence of geometry and nonlinear electrostatics on the orientation of adsorption.