Charge-Induced Unzipping of Isolated Proteins to a Defined Secondary Structure.
Charge-Induced Unzipping of Isolated Proteins to a Defined Secondary Structure.
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DOI：
10.1002/anie.201510983
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发表时间：
2016-03-01
期刊：
影响因子：
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通讯作者：
von Helden G
中科院分区：
文献类型：
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作者：
González Flórez AI;Mucha E;Ahn DS;Gewinner S;Schöllkopf W;Pagel K;von Helden G
本文结合实验和理论研究了分离蛋白的二级结构与电荷态的关系。在泛素蛋白和细胞色素c的红外光谱中，可以发现酰胺I （c =O拉伸）和酰胺II （N-H弯曲）带位于凝聚相蛋白的典型位置。对于高电荷态，出现了一个新的带，从低电荷态观察到的酰胺II带基本上红移。这些观测结果被解释为二级结构的库仑驱动转变，从大多数螺旋结构到扩展的C5型氢键结构。对这种解释的支持来自简单的能量考虑以及对模型肽的量子化学计算。这种二级结构的转变很可能是发生在质谱实验中的分离蛋白质的普遍现象。
Here we present a combined experimental and theoretical study on the secondary structure of isolated proteins as a function of charge state. In infrared spectra of the proteins ubiquitin and cytochrome c, amide I (C=O stretch) and amide II (N–H bend) bands can be found at positions that are typical for condensed‐phase proteins. For high charge states a new band appears, substantially red‐shifted from the amide II band observed at lower charge states. The observations are interpreted in terms of Coulomb‐driven transitions in secondary structures from mostly helical to extended C5‐type hydrogen‐bonded structures. Support for this interpretation comes from simple energy considerations as well as from quantum chemical calculations on model peptides. This transition in secondary structure is most likely universal for isolated proteins that occur in mass spectrometric experiments.