Interaction between β-lactoglobulin and EGCG under high-pressure by molecular dynamics simulation

Area of Science:

• Biochemistry
• Molecular Biophysics
• Food Science

Background:

• Beta-lactoglobulin (BLG) is a major whey protein.
• Epigallocatechin gallate (EGCG) is a potent antioxidant found in green tea.
• Understanding their interaction is crucial for food processing and health applications.

Purpose of the Study:

• To investigate the binding sites and stability of BLG-EGCG complex under high pressure (600 MPa).
• To elucidate the effects of high pressure on protein structure and small molecule binding interactions.

Main Methods:

• Molecular docking was used to identify potential binding sites of EGCG on BLG.
• Molecular dynamics (MD) simulations (150 ns) were performed to analyze structural changes and binding energies at different pressures (0.1 MPa and 600 MPa).

Main Results:

• EGCG binds to BLG at an internal site (site 1) and a surface site (site 2).
• High pressure (600 MPa) reduces protein fluctuation and solvent accessible surface area, increasing structural stability (α-helix and β-sheet content).
• High pressure weakens the binding energy of EGCG at both sites, particularly site 1, altering the dominant binding forces (van der Waals, hydrophobic interactions, hydrogen bonds).

Conclusions:

• High pressure significantly alters the binding mode and affinity of EGCG to BLG.
• While high pressure enhances BLG structural stability, it reduces the binding strength of EGCG, with site 2 becoming a stronger binding site than site 1 under pressure.