Lysine residues in the N-terminal huntingtin amphipathic α-helix play a key role in peptide aggregation
Lysine residues in the N-terminal huntingtin amphipathic α-helix play a key role in peptide aggregation
复制标题
DOI：
10.1002/jms.3504
复制
发表时间：
2015-01-01
影响因子：
2.3
通讯作者：
Valentine, Stephen J.
中科院分区：
文献类型：
--
作者：
Arndt, James R.;Brown, Robert J.;Valentine, Stephen J.
亨廷顿氏病是一种遗传性神经退行性疾病，由亨廷顿（htt）蛋白N-末端附近的多聚谷氨酰胺结构域的扩增引起，其导致蛋白质聚集体的形成。在这里，htt聚集体结构已被检查使用氢氘交换技术与串联质谱。研究的重点是17个残基的N-末端侧翼区的肽，已被证明可以改变htt聚集动力学和形态。采用电子转移解离的自上而下的测序策略用于确定可接近和受保护的氢的位置。在这些实验中，肽在中性pH的富氘溶剂中聚集，随后进行氘-氢反交换，然后进行快速淬灭、解聚和串联质谱分析。肽溶液的电喷雾电离产生[M+5 H]（5+）至[M+10 H]（10+）电荷状态，并显示存在多个肽序列，其差异在于单个谷氨酰胺残基。在电子转移解离分析中使用对应于完整肽的[M+7 H]（7+）至[M+9]（9+）电荷状态。在17个残基的N-末端道中观察到受保护残基的证据，并特别指出赖氨酸残基在htt聚集中可能发挥重要作用。版权所有（c）2015约翰威利父子有限公司
Huntington's disease is a genetic neurodegenerative disorder caused by an expansion in a polyglutamine domain near the N-terminus of the huntingtin (htt) protein that results in the formation of protein aggregates. Here, htt aggregate structure has been examined using hydrogen-deuterium exchange techniques coupled with tandem mass spectrometry. The focus of the study is on the 17-residue N-terminal flanking region of the peptide that has been shown to alter htt aggregation kinetics and morphology. A top-down sequencing strategy employing electron transfer dissociation is utilized to determine the location of accessible and protected hydrogens. In these experiments, peptides aggregate in a deuterium-rich solvent at neutral pH and are subsequently subjected to deuterium-hydrogen back-exchange followed by rapid quenching, disaggregation, and tandem mass spectrometry analysis. Electrospray ionization of the peptide solution produces the [M+5H](5+) to [M+10H](10+) charge states and reveals the presence of multiple peptide sequences differing by single glutamine residues. The [M+7H](7+) to [M+9](9+) charge states corresponding to the full peptide are used in the electron transfer dissociation analyses. Evidence for protected residues is observed in the 17-residue N-terminal tract and specifically points to lysine residues as potentially playing a significant role in htt aggregation. Copyright (c) 2015 John Wiley & Sons, Ltd.