Analysis of Secondary Structure Effects on the IR and Raman Spectra of Polypeptides in Terms of Localized Vibrations
Analysis of Secondary Structure Effects on the IR and Raman Spectra of Polypeptides in Terms of Localized Vibrations
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DOI：
10.1021/jp900354g
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发表时间：
2009-05-07
影响因子：
3.3
通讯作者：
Reiher, Markus
中科院分区：
文献类型：
--
作者：
Jacob, Christoph R.;Luber, Sandra;Reiher, Markus
我们演示了最近开发的根据局域模式分析计算振动光谱的方法[J. Chem. Phys. 2009，130，084106]如何应用于研究二级结构对多肽红外和拉曼光谱的影响。作为模型系统，考虑由α-螺旋和3（10）-螺旋构象的20个（S）-丙氨酸残基组成的多肽。详细分析了计算谱的几个特点。首先，我们展示了酰胺11带如何本地化的模式促进分解的总拉曼强度的某些原子团的贡献，以及如何这样的分析可以用来确定的起源差异的拉曼强度的两个螺旋。其次，我们演示了如何移位的两个考虑的结构之间的酰胺I带的位置可以合理化，以及如何观察到的强度分布内的酰胺I带可以通过考虑本地化模式之间的耦合常数来解释。第三，我们展示了如何本地化的模式可以用来分析的扩展酰胺III区域中发现的频带的位置，以及如何这样的分析使得有可能获得一个更好的理解如何结构变化影响酰胺III和C-α-H弯曲模式之间的耦合在这个区域。
We demonstrate how the recently developed methodology for the analysis of calculated vibrational spectra in terms of localized modes [J. Chem. Phys. 2009, 130, 084106] can be applied to investigate the influence of the secondary structure on infrared and Raman spectra of polypeptides. As a model system, a polypeptide consisting of 20 (S)-alanine residues in the conformation of an a-helix and of a 3(10)-helix is considered. Several features of the calculated spectra are analyzed in detail. First, we show for the amide 11 band how localized modes facilitate the decomposition of the total Raman intensities into contributions of certain groups of atoms, and how such an analysis can be used to identify the origin of differences in Raman intensity of the two helices. Second, we demonstrate how the shift of the position of the amide I band between the two considered structures can be rationalized and how the observed intensity distribution within the amide I band can be explained by considering the coupling constants between the localized modes. Third, we show how localized modes can be employed to analyze the positions of the bands found in the extended amide III region and how such an analysis makes it possible to gain a better understanding of how structural changes influence the coupling between the amide III and the C-alpha-H bending modes in this region.