Study of the Binding Interaction between Modified Glycinin and D-Galactose and Functions of the Resulting Complexes Via Multi-Spectroscopy and Molecular Dynamics Simulation

Abstract

This study evaluated the effects of D-galactose (DG) on the non-covalent binding capacity, structure, physicochemical properties and emulsification properties in pH shifting soy glycinin (11S). The results of structural and physicochemical analysis show that the conformation of pH shifting treated 11S (S-11S) are de-folded, the intermolecular disulfide bonds are significantly reduced, and the molecular flexibility is enhanced. At the same time, this study provides a molecular dynamics design method and enables the visualization of structural changes. The dispersion of S-11S structure leads to a significant increase in solubility and emulsification but a decrease in stability. The introduction of DG further improves the emulsification of S-11S and enhances the solubility and emulsification stability. Furthermore, it was fully revealed by multispectral, molecular docking and isothermal titration methods that S-11S and DG (S-11S/DG) formed uniform size nanoparticles through hydrophobic force and hydrogen bond driving, and the optimal binding ratio was 10.8:1. Although S-11S/DG belongs to non-covalent weak binding, DG stabilizes the conformation of S-11S. Therefore, the addition of DG can stabilize the overly discrete S-11S conformation and improve its functional characteristics. In conclusion, this study provides theoretical evidence for the potential application of modified protein and monosaccharide composite products in food and materials.

Keywords: Glycinin, D-galactose, Binding interaction, Molecular dynamics simulation, Molecular docking