Coordination features and affinity of the Cu²+ site in the α-synuclein protein of Parkinson's disease.
Coordination features and affinity of the Cu²+ site in the α-synuclein protein of Parkinson's disease.
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DOI：
10.1021/bi101912q
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发表时间：
2011-03-22
期刊：
影响因子：
2.9
通讯作者：
Millhauser GL
中科院分区：
文献类型：
--
作者：
Dudzik CG;Walter ED;Millhauser GL
帕金森氏病(PD)是第二种最常见的与年龄相关的神经退行性疾病，影响着1%的60岁以上人口。帕金森病的病理特征是细胞内主要由α-突触核蛋白(α-SYN)组成的包涵体。这些包裹体中还含有铜，Cu2+与α-SYN的相互作用可能在帕金森病的纤维形成中起重要作用。本文报道了Cu2+-α-SYN络合物的化学计量、亲和力和配位结构。电子顺磁共振滴定表明，单体α-SYN在蛋白质的N-末端结合了相当于1当量的Cu2+。接下来，EPR竞争技术证明了α-SYN与Cu2+结合的Kd≈为0.10 nm。最后，EPR和电子自旋回波调制(ESEEM)应用于一系列突变和截短的α-SYN结构，揭示了一个由N-端胺、Asp2酰胺主干和侧链羧基以及His50咪唑产生的配位球。这里发现的高结合亲和力，并与之前的测量结果一致，表明铜的吸收和封存可能是α-SYN自然功能的一部分，可能调节铜的氧化还原性质。这些结果进一步表明，N-末端与His50之间的远程相互作用可能减弱了α-SYN与脂膜的相互作用，从而动员了单体α-SYN并加速了纤维形成。
Parkinson’s disease (PD) is the second most prevalent age-related, neurodegenerative disorder, affecting >1% of the population over the age of 60. PD pathology is marked by intracellular inclusions composed primarily of the protein α-synuclein (α-syn). These inclusions also contain copper and the interaction of Cu2+ with α-syn may play an important role in PD fibrillogenesis. Here we report the stoichiometry, affinity and coordination structure of the Cu2+-α-syn complex. Electron Paramagnetic Resonance (EPR) titrations show that monomeric α-syn binds 1.0 equivalent of Cu2+ at the protein N-terminus. Next, an EPR competition technique demonstrates that α-syn binds Cu2+ with a Kd ≈ 0.10 nM. Finally, EPR and Electron Spin Echo Modulation (ESEEM) applied to a suite of mutant and truncated α-syn constructs reveal a coordination sphere arising from the N-terminal amine, the Asp2 amide backbone and side chain carboxyl group, and the His50 imidazole. The high binding affinity identified here, and in accord with previous measurements, suggests that copper uptake and sequestration may be a part of α-syn’s natural function, perhaps modulating copper’s redox properties. The findings further suggest that the long-range interaction between the N-terminus and His50 may have a weakening effect on α-syn interaction with lipid membranes thereby mobilizing monomeric α-syn and hastening fibrillogenesis.
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影响因子：
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