Theoretical and experimental perspectives of interaction mechanism between zein and lysozyme

The interaction mechanism of zein and lysozyme was investigated via multiple analytical methods combining with molecular dynamics simulations in this study. The results showed that the zein-lysozyme complex nanoparticles with a ratio of 2:1 were stable at pH 4.0. The electrostatic and hydrophobic interactions were the main driving forces for the formation of zein-lysozyme complexes. Hydrogen bonding also existed in the nanoparticles, but not the main driving force. Images of transmission electron microscope (TEM) showed the aggregation of samples, and the field emission scanning electron microscopy (FE-SEM) images showed that the surface morphology changes from smooth to rough and irregular. Molecular dynamics simulations elucidated that lysozyme preferred to bind to the protruding area of zein. The residues of P192, A193, A194, Y195, L196, Q198, L199, N203, Q245, and L253 in zein and the residues of D49, Y63, W64, A108, W109, and V110 in lysozyme contributed the most. These results can provide a scientific guideline for the potential application of zein-lysozyme nanoparticles as delivery systems or emulsion stabilizers in food industry.