Giraud Gerard, Wynne Klaas
Department of Physics, University of Strathclyde, Glasgow G4 0NG, Scotland.
J Am Chem Soc. 2002 Oct 16;124(41):12110-1. doi: 10.1021/ja027801h.
The low-frequency spectra of peptides and proteins in solution have been investigated with optical heterodyne-detected Raman-induced Kerr-effect spectroscopy. Spectra were obtained for di-l-alanine ALA(2) and poly-l-alanine (PLA) in dichloroacetic acid solution. The conformational dependence of those spectra at low frequency has been analyzed. ALA(2) displays a band centered at 50 cm-1, whereas the alpha-helical PLA shows two shoulders at 60 and 140 cm-1. The similarity of the spectral features observed in PLA to those in water can be explained by analogous acoustic translational modes in the hydrogen network of the PLA alpha-helix. The mostly alpha-helical protein lysozyme in aqueous solution has also been investigated and showed significantly more structure with modes at 10, 35, 73, 106, and 164 cm-1.
利用光学外差检测拉曼诱导克尔效应光谱研究了溶液中肽和蛋白质的低频光谱。获得了二 - L - 丙氨酸ALA(2)和聚 - L - 丙氨酸(PLA)在二氯乙酸溶液中的光谱。分析了这些光谱在低频下的构象依赖性。ALA(2)显示出一个以50 cm-1为中心的谱带，而α - 螺旋PLA在60和140 cm-1处有两个肩峰。在PLA中观察到的光谱特征与水中光谱特征的相似性可以通过PLAα - 螺旋氢网络中类似的声学平移模式来解释。还研究了水溶液中主要为α - 螺旋的蛋白质溶菌酶，其在10、35、73、106和164 cm-1处的模式显示出明显更多的结构。
