【摘要】：天然無(wú)結(jié)構(gòu)蛋白?-synuclein在帕金森癥(PD)患者腦部的路易小體中異常聚集,被認(rèn)為是引起PD的重要原因之一,但是目前關(guān)于?-synuclein的聚集機(jī)制仍沒(méi)有定論.蛋白質(zhì)二硫鍵異構(gòu)酶(PDI)是細(xì)胞內(nèi)質(zhì)網(wǎng)中重要的分子伴侶蛋白,能夠阻止內(nèi)質(zhì)網(wǎng)中無(wú)結(jié)構(gòu)蛋白的聚集.在PD患者的腦細(xì)胞內(nèi)發(fā)現(xiàn)PDI過(guò)量表達(dá),且酶活性位點(diǎn)半胱氨酸被亞硝基化使其活性受到抑制.體外實(shí)驗(yàn)證明,PDI能夠抑制?-synuclein的聚集,但其具體的分子機(jī)制還不清楚,研究PDI抑制?-synuclein聚集的具體機(jī)制可能對(duì)于PD治療有重要意義.該文利用核磁共振(NMR)方法研究了?-synuclein與PDI的相互作用,發(fā)現(xiàn)?-synuclein與PDI的結(jié)合位點(diǎn)位于?-synuclein的N端;將PDI所有的6個(gè)半胱氨酸突變成絲氨酸,得到突變體PDI C-S,發(fā)現(xiàn)?-synuclein與PDI C-S的結(jié)合位點(diǎn)則位于其C末端;熒光實(shí)驗(yàn)結(jié)果表明突變體PDI C-S對(duì)?-synuclein纖維化聚集的抑制作用減弱,說(shuō)明PDI抑制?-synuclein的纖維化聚集主要是通過(guò)與?-synuclein的N端殘基結(jié)合來(lái)實(shí)現(xiàn)的.
[Abstract]:The abnormal aggregation of natural structural protein-synuclein in the Louis bodies of the brain of Parkinson's disease patients with (PD) is considered to be one of the important causes of PD. However, the mechanism of the aggregation of?-synuclein is still unknown. Protein disulfide isomerase (PDI) is an important molecular chaperone protein in the endoplasmic reticulum, which can prevent the aggregation of unstructured proteins in the endoplasmic reticulum. Over-expression of PDI was found in the brain cells of PD patients, and cysteine, the enzyme activity site, was inhibited by nitrosation. It has been proved in vitro that PDI can inhibit the aggregation of?-synuclein, but its molecular mechanism is still unclear. The study of the mechanism of PDI inhibiting?-synuclein aggregation may be of great significance for the treatment of PD. The interaction between?-synuclein and PDI was studied by nuclear magnetic resonance (NMR). It was found that the binding site between-synuclein and PDI was at the N-terminal of?-synuclein. All six cysteine mutants of PDI were transformed into serine, and the mutant PDI Cass S was obtained. It was found that the binding site of?-synuclein to PDI Cass was located at the C-terminal of the mutant. The results of fluorescence assay showed that the inhibitory effect of mutant PDI C _ (S) on fibrosis aggregation of?-synuclein was weakened, indicating that the inhibition of PDI on fibrosis aggregation of?-synuclein was mainly achieved by binding to N-terminal residues of?-synuclein.
【作者單位】： 中國(guó)科學(xué)院生物磁共振分析重點(diǎn)實(shí)驗(yàn)室 波譜與原子分子物理國(guó)家重點(diǎn)實(shí)驗(yàn)室 武漢磁共振中心(中國(guó)科學(xué)院武漢物理與數(shù)學(xué)研究所);中國(guó)科學(xué)院大學(xué);
【基金】：國(guó)家自然科學(xué)基金資助項(xiàng)目(21203243)
【分類號(hào)】：R742.5

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