Nie Rong-Zu, Zhu Wei, Peng Jin-Ming, Ge Zhen-Zhen, Li Chun-Mei
College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; Key Laboratory of Environment Correlative Food Science, Huazhong Agricultural University, Ministry of Education, Wuhan 430070, China.
Biophys Chem. 2017 Nov;230:1-9. doi: 10.1016/j.bpc.2017.07.009. Epub 2017 Jul 31.
In the present study, the disruptive effects of epigallocatechin-3-gallate (EGCG) and A-type dimeric epigallocatechin-3-gallate (A-type EGCG dimer) on the preformed bovine insulin amyloid fibrils were studied by several biophysical methods including thioflavin-T (ThT) fluorescence assay, 1-anilinonaphthalene-8-sulfonic (ANS) fluorescence assay, Congo red (CR) binding assay, dynamic light scattering (DLS), transmission electron microscopy (TEM), Gel electrophoresis (SDS-PAGE) and Bradford assay. Our results demonstrated that A-type EGCG dimer showed significantly more potential disaggregative effects on the bovine insulin amyloid fibrils than EGCG. A-type EGCG dimer could not only dramatically promote the disaggregation of the preformed bovine insulin amyloid fibrils, but also restructure the amyloid fibrils into amorphous aggregates. While, EGCG could only shorten and thin the fibrils, but induce no small amorphous aggregates. Our present results provided additional evidence for the more potent disaggregation effects of dimeric polyphenols than monomeric polyphenols and suggested that A-type EGCG dimer seems to have potential application as an excellent anti-amyloidogenic agent.
在本研究中，通过多种生物物理方法，包括硫黄素-T（ThT）荧光测定、1-苯胺基萘-8-磺酸（ANS）荧光测定、刚果红（CR）结合测定、动态光散射（DLS）、透射电子显微镜（TEM）、凝胶电泳（SDS-PAGE）和Bradford测定，研究了表没食子儿茶素-3-没食子酸酯（EGCG）和A型二聚体表没食子儿茶素-3-没食子酸酯（A型EGCG二聚体）对预先形成的牛胰岛素淀粉样纤维的破坏作用。我们的结果表明，A型EGCG二聚体对牛胰岛素淀粉样纤维的解聚作用比EGCG显著更强。A型EGCG二聚体不仅能显著促进预先形成的牛胰岛素淀粉样纤维的解聚，还能将淀粉样纤维重构为无定形聚集体。而EGCG只能使纤维变短变细，但不会诱导形成小的无定形聚集体。我们目前的结果为二聚多酚比单体多酚具有更强的解聚作用提供了额外证据，并表明A型EGCG二聚体似乎有作为一种优秀的抗淀粉样蛋白生成剂的潜在应用。
