Different types of anions mediated the formation of rice glutelin fibrils: Aggregation behaviors and structural characteristics

Anions have more pronounced effect on the aggregation power of proteins than cations. Herein, the effect of different types of anions on rice glutelin (RG) based fibrils formation was investigated. The fibrils yield and growth rate of RG were enhanced with various anions, due to the specific ions effect and intermolecular interaction. It was observed that the fibrillization rate of RG followed the specific order: Br^- > I^- > F^- > NO₃^- > Cl^- > CH₃COO^- > ClO^-. In addition, the chaotropes (e.g., I^-) interacted more favorably with hydrophobic residues to form needle-like periodic structure, whereas the kosmotropes (e.g., CH₃COO^-) preferred to form larger fibrils clusters due to the stronger shielding effect. Consequently, various anions profoundly influenced the unfolding, dimerization, reorganization of protein, as well as the formation of crucial β-sheet structure. This study helps to understand how the structure of fibrils can be tuned through different anions.