Pathogenic Mutations Shift the Equilibria of α-Synuclein Single Molecules towards Structured Conformers
Pathogenic Mutations Shift the Equilibria of α-Synuclein Single Molecules towards Structured Conformers
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DOI：
10.1002/cbic.200800581
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发表时间：
2009-01-05
期刊：
影响因子：
3.2
通讯作者：
Samori, Bruno
中科院分区：
文献类型：
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作者：
Brucale, Marco;Sandal, Massimo;Samori, Bruno
α-突触核蛋白(α-Syn)是一种丰富的大脑蛋白质，其突变与早发性帕金森病(PD)有关。我们最近通过单分子力谱(SMFS)方法证明，在几种与帕金森病致病无关的条件下，单体野生型(WT)α-Syn的构象平衡向含有β的结构移动。在这里，我们遵循先前对WTα-Syn所采用的一些方法来表征病理性α-Syn突变体A30P、A53T和E46K的构象异质性。与不同作者迄今为此采用的整体集合平均光谱相反，我们的单分子方法监测到了突变体相对于WT序列的构象行为的显著差异。我们发现，所有突变体都比WT有更高的倾向采用与获得β结构相容的单体致密构象。突变体A30P和A53T表现出与E46K相似的构象平衡，这与E46K的构象平衡显著不同。另一类由机械弱相互作用稳定的构象在突变体中显示出比WT蛋白更高的变化。在A30P突变体中，这些相互作用相对较强，因此相应的构象可能更具结构性。突变体的更具结构和球状的构象可以解释它们相对于WT更高的聚集倾向。
alpha-synuclein (alpha-Syn) is an abundant brain protein whose mutations have been linked to early-onset Parkinson's disease (PD). We recently demonstrated, by means of a single-molecule force spectroscopy (SMFS) methodology, that the conformational equilibrium of monomeric wild-type (WT) alpha-Syn shifts toward beta-containing, structures in several unrelated conditions linked to PD pathogenicity. Herein, we follow the some methodology previously employed for WT alpha-Syn to characterize the conformational heterogeneity of pathological alpha-Syn mutants A30P, A53T, and E46K Contrary to the bulk ensemble-averaged spectroscopies so far employed to this end by different authors, our single-molecule methodology monitored marked differences in the conformational behaviors of the mutants with respect to the WT sequence. We found that all the mutants have a much higher propensity than the WT to adopt a monomeric compact conformation that is compatible with the acquiring of beta structure. Mutants A30P and A53T show a similar conformational equilibrium that is significantly different from that of E46K Another class of conformations, stabilized by mechanically weak interactions (MINI), shows a higher variety in the mutants than in the WT protein. In the A30P mutant these interactions are relatively stronger, and therefore the corresponding conformations are possibly more Structured. The more structured and globular conformations of the mutants can explain their higher propensity to aggregate with respect to the WT.