BSA structural changes during homomolecular exchange between the adsorbed and the dissolved states

Area of Science:

• Biochemistry
• Materials Science
• Protein Chemistry

Background:

• Bovine serum albumin (BSA) is a crucial protein with diverse applications.
• Understanding protein-surface interactions is vital for biomaterials and drug delivery.
• Surface properties can significantly alter protein structure and function.

Purpose of the Study:

• To investigate the structural and thermostability changes of BSA after adsorption and desorption from different surfaces.
• To compare the effects of hydrophilic (silica) and hydrophobic (polystyrene) surfaces on BSA.
• To determine the reversibility of BSA structural changes induced by surface interactions.

Main Methods:

• Circular dichroism (CD) spectroscopy to analyze secondary structure.
• Differential scanning calorimetry (DSC) to assess thermostability.
• Adsorption and desorption experiments using silica and polystyrene particles.

Main Results:

• BSA structural perturbations induced by silica were reversible, with complete recovery of native structure and stability.
• Adsorption and desorption from polystyrene led to irreversible changes in BSA stability and secondary structure.
• Exchanged BSA exhibited higher denaturation temperatures and lower denaturation enthalpy compared to native BSA.
• A reduction in alpha-helix content and an increase in beta-turn fraction were observed in BSA desorbed from polystyrene.
• These effects were more pronounced on less crowded polystyrene surfaces, suggesting aggregation.

Conclusions:

• Hydrophilic surfaces like silica induce reversible structural changes in BSA.
• Hydrophobic surfaces like polystyrene cause irreversible conformational changes in BSA, potentially due to aggregation.
• Surface chemistry significantly impacts protein stability and structure, with implications for protein-surface interactions in various applications.