Effect of different oligomerization assemblies of γ‐conglutin on its interaction behavior with vitexin.

BACKGROUND: Several different factors underlie the molecular mechanisms of phenolic compound‐protein interactions. They include the environmental conditions. In the case of γ‐conglutin, pH conditions translate directly into the adoption of two distinct oligomeric assemblies, i.e. hexameric (pH 7.5) or monomeric (pH 4.5). This paper reports research on the pH‐dependent oligomerization of γ‐conglutin in terms of its ability to form complexes with a model flavonoid (vitexin). RESULTS: Fluorescence‐quenching thermodynamic measurements indicate that hydrogen bonds, electrostatic forces, and van der Waals interactions are the main driving forces involved in the complex formation. The interaction turned out to be a spontaneous and exothermic process. Assessment of structural composition (secondary structure changes and arrangement/dynamics of aromatic amino acids), molecular size, and the thermal stability of the different oligomeric forms showed that γ‐conglutin in a monomeric state was less affected by vitexin during the interaction. CONCLUSION: The data show precisely how environmental conditions might influence phenolic compound‐protein complex formation directly. This knowledge is essential for the preparation of food products containing γ‐conglutin. The results can contribute to a better understanding of the detailed fate of this unique health‐promoting lupin seed protein after its intake. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]