Study of the weak interaction mechanism of ovalbumin and caffeic acid using fluorescence spectroscopy and molecular dynamics simulation

Abstract

With the increasing demand for functional foods, the study on binding of active molecules and ovalbumin (OVA) via weak interaction has attracted widespread attention. In this work, the interaction mechanism of OVA and caffeic acid (CA) was revealed using fluorescence spectroscopy and dynamics simulation. The CA-induced fluorescence decrease of OVA was static quenching. Their binding complex had about 1 binding site and a 3.39 × 10⁵ L·mol^-1 affinity ability. Based on thermodynamic calculations and molecular dynamics simulation, the complex structure of OVA and CA were stable using hydrophobic interactions as the main force, where CA preferred to interact with a stable binding pocket consisting of E256, E25, and V200 with N24 amino acid residues. In the binding process of CA and OVA, the conformation of OVA was altered with a slight reduction of α-helix and β-sheet. The reduced molecular volume and more compact structure of the protein indicated that CA is beneficial to the structural stability of OVA. The research provides some new insights into the interaction between dietary proteins and polyphenols, expanding the application prospects of OVA as a carrier.

Keywords: Caffeic acid; Molecular dynamics simulation; Ovalbumin; Weak interaction.