Resveratrol Induces the Conversion from Amyloid to Amorphous Aggregation of β-lactoglobulin

Background: Protein aggregation is a wide-ranging phenomenon. Protein aggregation mainly includes two types: one is amorphous aggregation, the other is amyloid aggregation. In particular, amyloid aggregation in vivo can cause several fatal diseases. We have investigated the influence of resveratrol on the amyloid aggregation of β-lactoglobulin. The results demonstrated resveratrol inhibited the amyloid aggregation and enhanced the amorphous aggregation of β- lactoglobulin. Objectives: The main objective of this study was to investigate the effects of resveratrol on the amyloid aggregation of β-lactoglobulin. Methods: β-lactoglobulin was incubated at pH 2.0 and 70 °C. ThT fluorescence, Congo red and transmission electron microscopy were used to monitor the formation of amyloid aggregates. In addition, resveratrol was added intoβ-lactoglobulin solutions. Intrinsic fluorescence, Circular dichroism and 1-Anilinonaphthalene-8-sulfonic Acid (ANS) fluorescence were used to investigate conformational and hydrophobic changes. Furthermore, we also studied the effect of resveratrol on the amyloid aggregation of β-lactoglobulin by using ThT fluorescence, Congo red and transmission electron microscopy at acidic pH and high temperature. Results: ThT fluorescence, Congo red and transmission electron microscopy analysis showed that β-lactoglobulin could form the amyloid fibrils when it was incubated under acidic pH and high temperature conditions. At the same time, the analysis also demonstrated resveratrol inhibited the formation of amyloid aggregates and enhanced the formation amorphous aggregates. Intrinsic fluorescence, Circular dichroism and 1-Anilinonaphthalene-8-sulfonic Acid (ANS) fluorescence analysis indicated that resveratrol could alter the conformation and increased the hydrophobicity of β- lactoglobulin. Conclusion: Our results indicated that resveratrol could effectively inhibit the formation of amyloid aggregates and enhance the formation of amorphous aggregates of β-lactoglobulin. Thus, resveratrol could be a potential inhibitor for preventing the formation of amyloid aggregates. Keywords: Amorphous aggregation, amyloid aggregation, hydrophobic interactions, β-lactoglobulin (β-LG), resveratrol, transmission electron microscopy (TEM).