Mechanistic Insights into Masked Fumonisin B1–Gliadin Complex Formation in Wheat

Fumonisin B1 (FB1) is a widespread mycotoxin in cereals that poses severe health risks to humans and animals. However, its masked forms often escape routine detection, leading to an underestimation of contamination levels. To elucidate this masking mechanism, the noncovalent interactions between FB1 and gliadin were investigated. The results indicate that FB1 binds to gliadin through a static quenching mechanism, forming a stable ground-state complex. This spontaneous and exothermic binding is primarily driven by hydrogen bonds. Additionally, the binding of FB1 induces an apparent redistribution of the protein's secondary structure, characterized by an increase in α-helix content and a reduce in β-sheet content. Spatially, FB1 anchors itself within a hydrophobic pocket of gliadin and is stabilized by a network of hydrogen bonds. Revealing the formation mechanism of this FB1-protein complex provides a critical molecular basis for improving mycotoxin extraction methods and accurately assessing true fumonisin exposure in wheat-based products.