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

As D-galactose (DG) reacts with soy protein during the processing or storage of soy-containing food products, exploring the mechanism of binding of modified proteins to DG is necessary. In this study, the effect of pH shifting on glycinin (11S) and the mechanism of binding of modified 11S (S-11S) to DG were analyzed by multi-spectroscopy, molecular dynamics, and molecular docking. On the one hand, upon pH shifting, 11S de-folded, the 11S structure tended to be disordered, the microenvironment of tryptophan changed. On the other hand, S-11S formed weakly bound complexes with DG via hydrophobic interactions and hydrogen bond. Due to the molecular specificity of DG, the content of S-S bond and physical properties of the complexes demonstrated inverse dependences on the concentration of DG. Preparation of complexes of S-11S and DG provides a new theoretical idea for the application of soy protein in emulsion, foaming.

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