波谱学杂志 ›› 2017, Vol. 34 ›› Issue (2): 131-136.doi: 10.11938/cjmr20170201

• 研究论文 • 上一篇    下一篇

PDI抑制α-synuclein纤维化聚集作用机制研究

陈艳华1,2, 张则婷1, 白佳1,2, 刘晓黎1, 刘买利1, 李从刚1   

  1. 1. 中国科学院生物磁共振分析重点实验室, 波谱与原子分子物理国家重点实验室, 武汉磁共振中心(中国科学院 武汉物理与数学研究所), 湖北 武汉 430071;
    2. 中国科学院大学, 北京 100049
  • 收稿日期:2016-04-22 修回日期:2017-04-19 出版日期:2017-06-05 发布日期:2017-06-05
  • 通讯作者: 张则婷,Tel:027-87197391,E-mail:zhangzeting@wipm.ac.cn. E-mail:zhangzeting@wipm.ac.cn
  • 基金资助:
    国家自然科学基金资助项目(21203243).

Inhibition Mechanisms of Protein Disulfide Isomerase on α-Synuclein Fibril Aggregation

CHEN Yan-hua1,2, ZHANG Ze-ting1, BAI Jia1,2, LIU Xiao-li1, LIU Mai-li1, LI Cong-gang1   

  1. 1. CAS Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan(Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences), Wuhan 430071, China;
    2. University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2016-04-22 Revised:2017-04-19 Online:2017-06-05 Published:2017-06-05

摘要: 天然无结构蛋白α-synuclein在帕金森症(PD)患者脑部的路易小体中异常聚集,被认为是引起PD的重要原因之一,但是目前关于α-synuclein的聚集机制仍没有定论.蛋白质二硫键异构酶(PDI)是细胞内质网中重要的分子伴侣蛋白,能够阻止内质网中无结构蛋白的聚集.在PD患者的脑细胞内发现PDI过量表达,且酶活性位点半胱氨酸被亚硝基化使其活性受到抑制.体外实验证明,PDI能够抑制α-synuclein的聚集,但其具体的分子机制还不清楚,研究PDI抑制α-synuclein聚集的具体机制可能对于PD治疗有重要意义.该文利用核磁共振(NMR)方法研究了α-synuclein与PDI的相互作用,发现α-synuclein与PDI的结合位点位于α-synuclein的N端;将PDI所有的6个半胱氨酸突变成丝氨酸,得到突变体PDI C-S,发现α-synuclein与PDI C-S的结合位点则位于其C末端;荧光实验结果表明突变体PDI C-S对α-synuclein纤维化聚集的抑制作用减弱,说明PDI抑制α-synuclein的纤维化聚集主要是通过与α-synuclein的N端残基结合来实现的.

关键词: 相互作用, α-synuclein, 蛋白质二硫键异构酶(PDI), 核磁共振(NMR)

Abstract: Abnormal aggregation of α-synuclein, an intrinsically disordered protein in Lewy bodies, is considered a hallmark of Parkinson's disease (PD). The mechanisms underlying abnormal α-synuclein aggregation, however, are yet to be understood. Protein disulfide isomerase (PDI) is an important molecular chaperone in the endoplasmic reticulum, which can prevent disordered protein forming aggregation. PDI is shown to be overexpressed in the brain of PD patients, but with reduced activity due to S-nitrosylation of the cysteine residues in the active site. In vitro experiments have demonstrated that PDI can inhibit the aggregation of α-synuclein with unknown mechanisms. Hence, it may be of importance to study the inhibition mechanisms of PDI on α-synuclein aggregation. In this study, the interaction between α-synuclein and PDI was studied by NMR spectroscopy. It was found that the binding sites between the two are located on the N-terminal of α-synuclein. A variant PDI (PDI C-S) was prepared, in which all six cysteines were mutated to serines. It was found that the binding sites between PDI C-S and α-synuclein are located on the C-terminus of α-synuclein. The results of thioflavin T (ThT) fluorescence experiment showed that the inhibition activity of PDI C-S on α-synuclein aggregation was lower than the wild type, suggesting that wild type PDI may inhibit α-synuclein aggregation through binding to its N-terminal.

Key words: interaction, protein disulfide isomerase (PDI), NMR, α-synuclein

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