Chiral sum frequency generation for in situ probing proton exchange in antiparallel β-sheets at interfaces.
Chiral sum frequency generation for in situ probing proton exchange in antiparallel β-sheets at interfaces.
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DOI：
10.1021/ja3119527
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发表时间：
2013-03-06
影响因子：
15
通讯作者：
Yan, Elsa C. Y.
中科院分区：
文献类型：
--
作者：
Fu, Li;Xiao, Dequan;Wang, Zhuguang;Batista, Victor S.;Yan, Elsa C. Y.
研究蛋白质中氢/氘（H/D）交换可以为蛋白质结构和动力学提供有价值的见解。有几种技术可用于探测体溶液中的H/D交换，包括核磁共振、质谱和傅里叶变换红外光谱。然而，探测界面上的H/D交换是具有挑战性的，因为它需要表面选择方法。在这里，我们介绍了原位手性和频率产生（cSFG）光谱和cSFG光谱的从头算模拟的结合，作为一种强大的方法来探测界面上H/D交换的动态。该方法用于表征反平行β-片肽LK7β的H/D交换。我们首次报道了在空气/水界面的反平行结构中，D-to- h的交换速率比H-to-D的交换速率快一个数量级，这与现有的知识一致，即在水中O-H/D的解离是速率限制步骤，并且O-D键的断裂比O-H键的断裂慢。报告的分析还提供了对肽骨架中几种振动模式及其耦合的基本理解，这些模式很难用常规方法表征，包括肽振动模式的各种组合的费米共振，如酰胺I和酰胺II， C-N拉伸和N-H/N-D弯曲。这些结果表明，cSFG是一种灵敏的技术，用于探测界面蛋白质中H/D交换动力学，具有高信噪比的N-H/N-D拉伸带，不受水O-H/O-D拉伸的背景影响。
Studying hydrogen/deuterium (H/D) exchange in proteins can provide valuable insight on protein structure and dynamics. Several techniques are available for probing H/D exchange in the bulk solution, including NMR, mass spectroscopy and Fourier transform infrared spectroscopy. However, probing H/D exchange at interfaces is challenging since it requires surface-selective methods. Here, we introduce the combination of in situ chiral sum frequency generation (cSFG) spectroscopy and ab initio simulations of cSFG spectra as a powerful methodology to probe the dynamics of H/D exchange at interfaces. This method is applied to characterize H/D exchange in the antiparallel β-sheet peptide LK7β. We report here for the first time that the rate of D-to-H exchange is about one order of magnitude faster than H-to-D exchange in the anti-parallel structure at the air/water interface, which is consistent with the existing knowledge that O-H/D dissociation in water is the rate limiting step, and breaking the O-D bond is slower than breaking the O-H bond. The reported analysis also provides fundamental understanding of several vibrational modes and their couplings in peptide backbones that have been difficult to characterize by conventional methods, including Fermi resonances of various combinations of peptide vibrational modes such as amide I and amide II, C-N stretch, and N-H/N-D bending. These results demonstrate cSFG as a sensitive technique for probing the kinetics of H/D exchange in proteins at interfaces, with high signal-to-noise N-H/N-D stretch bands that are free of background from the water O-H/O-D stretch.
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影响因子：
15
作者：
Fu, Li;Ma, Gang;Yan, Elsa C. Y.
通讯作者：
Yan, Elsa C. Y.
影响因子：
2.5
作者：
KRIMM, S;DWIVEDI, AM
通讯作者：
DWIVEDI, AM
影响因子：
2.9
作者：
Kubelka, J;Keiderling, TA
通讯作者：
Keiderling, TA
影响因子：
2.9
作者：
LAL, BB;NAFIE, LA
通讯作者：
NAFIE, LA
影响因子：
2
作者：
Ji, N;Shen, YR
通讯作者：
Shen, YR