Magnesium ions regulated ovalbumin-lysozyme heteroprotein complex: Aggregation kinetics, thermodynamics and...

Area of Science:

• Biochemistry
• Protein aggregation
• Ion-protein interactions

Background:

• Protein aggregation is crucial in biological systems and disease.
• Understanding heteroprotein aggregation dynamics is complex.
• Ovalbumin (OVA) and lysozyme (LYS) are model proteins for studying interactions.

Purpose of the Study:

• To investigate magnesium ion (Mg2+) effects on OVA-LYS heteroprotein aggregation.
• To explore the relationship between aggregation behavior, protein structure, and thermal stability.
• To elucidate the role of electrostatic interactions and ion shielding in protein complex formation.

Main Methods:

• Aggregation kinetics modeling to determine aggregation rates (kapp) and maximum absorbance (Amax).
• Differential Scanning Calorimetry (DSC) to assess thermal denaturation temperature (Td) and enthalpy (ΔH).
• Molecular dynamics simulations to visualize conformational changes and complex stability.
• MgCl2 treatment to study ion-shielding effects on protein interactions.

Main Results:

• OVA-LYS complex exhibited aggregation and thermal properties intermediate to OVA and LYS alone.
• Electrostatic interactions enhanced OVA-LYS thermal stability, slowing aggregation.
• Molecular dynamics confirmed stable binary protein complex conformations.
• MgCl2 weakened OVA-LYS interactions via Debye shielding, increasing thermal stability and promoting amorphous precipitates over coacervates.

Conclusions:

• Protein-protein electrostatic interactions modulate heteroprotein aggregation and stability.
• Magnesium ions regulate OVA-LYS aggregation behavior through Debye shielding.
• This study provides insights into ion-driven protein aggregation mechanisms.