Molecular mechanism of hidden matrix-bound deoxynivalenol binding to proteins in wheat.

Protein-bound hidden deoxynivalenol (DON) poses significant health risks during mycotoxin degradation in wheat matrices. This study combined spectroscopic analyses and molecular docking to elucidate DON-gliadin interaction mechanisms. DON induced static fluorescence quenching of gliadin (quenching constant: 0.98 × 103 L·mol-1) and formed a stable 1:1 complex through hydrogen bonding, van der Waals, and hydrophobic interactions (ΔG = -14.07 kJ·mol-1; binding constant = 0.289 × 103 L·mol-1). The interaction altered gliadin secondary structure, reducing α-helices (4.29%) and β-sheets (2.86%) while increasing β-turns (3.75%) and random coils (3.35%), and decreased surface hydrophobicity. These structural changes were confirmed by FTIR, synchronous fluorescence, and CD spectroscopy. Molecular docking further showed DON binds to residues in the gliadin domain, with Gln223 and Phe238 playing key roles (binding energy: -5.851 kcal/mol; binding distances: 1.81 Å and 5.41 Å). These findings support the development of targeted detoxification strategies for hidden DON, contributing to improved wheat safety and protection of human health.