Electrostatic interactions in protein adsorption probed by comparing lysozyme and succinylated lysozyme

Area of Science:

• Biochemistry
• Surface Science
• Protein Chemistry

Background:

• Protein adsorption is crucial in various applications, including biomaterials and diagnostics.
• Understanding the forces driving protein-surface interactions is essential for controlling adsorption.
• Electrostatic interactions play a significant role in protein adsorption phenomena.

Purpose of the Study:

• To investigate the influence of electrostatic interactions on protein adsorption.
• To compare the adsorption behavior of native lysozyme and succinylated lysozyme at silica surfaces.
• To elucidate the primary driving forces behind protein adsorption under varying conditions.

Main Methods:

• Comparative adsorption studies of lysozyme and succinylated lysozyme on silica.
• Analysis of adsorption as a function of pH and ionic strength.
• Assessment of the impact of protein charge modification (succinylation) on adsorption.

Main Results:

• Protein adsorption exhibited a pH-dependent maximum for both lysozyme and succinylated lysozyme.
• The adsorption maximum correlated with the isoelectric points of the proteins.
• Higher ionic strength increased adsorption when electrostatic repulsion dominated and decreased it under attraction.

Conclusions:

• Electrostatic interactions are the primary determinant of lysozyme and succinylated lysozyme adsorption onto silica.
• Protein stability changes due to succinylation were secondary to electrostatic effects on adsorption.
• Adsorption behavior can be effectively modulated by controlling pH and ionic strength to leverage electrostatic forces.