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PNAS:绿茶中EGCG可解除蛋白质异常沉积带来的毒性

来源:新华网 2010-04-16 13:51

德国马克斯·德尔布吕克分子医学中心4月14日报告的一项最新研究成果显示,绿茶中活性物质EGCG(表没食子儿茶素没食子酸酯)可解除与老年痴呆症等疾病有关的蛋白质异常沉积带来的毒性。

研究人员说,β淀粉样蛋白是由蛋白质的错误折叠导致的,它的异常沉积对神经细胞有致命毒性,可导致细胞死亡。β淀粉样蛋白异常沉积是老年痴呆症和帕金森氏症等疾病的重要病因。

马克斯·德尔布吕克分子医学中心研究人员在试管和细胞培养基实验中发现,植入这种有毒蛋白沉积会导致神经细胞新陈代谢水平下降,细胞膜也会变得不稳定。而一旦有绿茶活性物质EGCG介入,这些细胞受损的现象会消失。EGCG解毒作用的机理是其首先与纤维状β淀粉样蛋白结合,将后者转变成对神经细胞无害、之后又会被细胞分解的球状蛋白聚集体。

EGCG不仅能解毒,还能防毒。马克斯·德尔布吕克分子医学中心此前的一项研究已经发现EGCG有防患于未然的作用:它能够与还没有折叠的蛋白质结合,阻止其错误折叠,从而阻止与老年痴呆症、帕金森氏症和亨廷顿舞蹈病有关的有毒蛋白沉积的形成。

这一成果发表在最新一期的PNAS上。(生物谷Bioon.com)

相关阅读:

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IJC:蘑菇和绿茶可预防乳腺癌

JCO:绿茶提取物可治慢性淋巴白血病

CPR:绿茶成分或可减缓前列腺癌生长

生物谷推荐原始出处:

PNAS  April 12, 2010, doi: 10.1073/pnas.0910723107

EGCG remodels mature α-synuclein and amyloid-β fibrils and reduces cellular toxicity

Jan Bieschke1, Jenny Russ, Ralf P. Friedrich, Dagmar E. Ehrnhoefer2, Heike Wobst, Katja Neugebauer, and Erich E. Wanker1

Protein misfolding and formation of β-sheet-rich amyloid fibrils or aggregates is related to cellular toxicity and decay in various human disorders including Alzheimer’s and Parkinson’s disease. Recently, we demonstrated that the polyphenol (-)-epi-gallocatechine gallate (EGCG) inhibits α-synuclein and amyloid-β fibrillogenesis. It associates with natively unfolded polypeptides and promotes the self-assembly of unstructured oligomers of a new type. Whether EGCG disassembles preformed amyloid fibrils, however, remained unclear. Here, we show that EGCG has the ability to convert large, mature α-synuclein and amyloid-β fibrils into smaller, amorphous protein aggregates that are nontoxic to mammalian cells. Mechanistic studies revealed that the compound directly binds to β-sheet-rich aggregates and mediates the conformational change without their disassembly into monomers or small diffusible oligomers. These findings suggest that EGCG is a potent remodeling agent of mature amyloid fibrils.

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