论文部分内容阅读
天然无结构蛋白?-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?-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?-synuclein的聚集,但其具体的分子机制还不清楚,研究PDI抑制?-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?-synuclein与PDI的相互作用,发现?-synuclein与PDI的结合位点位于?-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?-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?-synuclein纤维化聚集的抑制作用减弱,说明PDI抑制?-synuclein的纤维化聚集主要是通过与?-synuclein的N端残基结合来实现的.
Natural unstructured protein? Synuclein abnormal aggregation in the brain of Parkinson’s disease (PD) patients is considered one of the major causes of PD, but the current mechanism of? -synuclein aggregation remains to be determined.Protein Disulfide isomerase (PDI) is an important molecular chaperone protein in the endoplasmic reticulum, which can prevent the aggregation of unstructural proteins in the endoplasmic reticulum. PDI is over-expressed in brain cells of PD patients, Cysteine is nitrosated to inhibit its activity.In vitro experiments show that, PDI can inhibit? -synuclein aggregation, but its specific molecular mechanism is unclear, the study of PDI inhibition? Specific mechanism of synuclein aggregation may be PD treatment is of great significance.In this paper, the interaction between? -synuclein and PDI was studied by using nuclear magnetic resonance (NMR) method and found that the binding site of? -synuclein and PDI was located at the N-terminal of? -synuclein; Cysteine mutated to serine to get mutated PDI CS and found? -synuclein and PDI CS binding site is located in its C-terminal; fluorescence experiments showed that mutant PDI CS on? -synuclein fibrosis and aggregation inhibition Weakening, indicating PDI suppression Fibrosis-Synuclein Fibrosis Aggregation is mainly achieved by binding to the N-terminal residue of? -synuclein.