Explore the interaction mechanism between zein and EGCG using multi-spectroscopy and molecular dynamics simulation methods

Zein as a kind of carrier material has attracted extensive interest, while the interaction mechanism between zein and nutrients is still elusive. In this work, the binding mechanism of zein with epigallocatechin-3-gallate (EGCG) was investigated via multi-spectroscopy and molecular dynamics (MD) simulation. The quenching of zein by EGCG is mainly static quenching, and the secondary structure of zein is slightly changed after the binding of EGCG to zein. The formation of Zein-EGCG complexes was confirmed by ultraviolet–visible (UV–Vis) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). Molecular dynamics (MD) simulation clarified that the EGCG prefers to bind to the pocket of zein formed by residues Y171, Q174, L176 and L205. Electrostatic and van der Waals interactions played a dominant role for the binding of EGCG to zein, which was consistent with the results by fourier transform infrared spectroscopy (FTIR) and thermodynamic analysis. This study provides new insights into the interaction mechanism between zein and EGCG, which is very important to develop plant protein as tea polyphenol delivery system.