Hydration dependence of backbone and side chain polylysine dynamics: A 13C solid‐state NMR and IR spectroscopy study
Hydration dependence of backbone and side chain polylysine dynamics: A 13C solid‐state NMR and IR spectroscopy study
复制标题
主链和侧链聚赖氨酸动力学的水合依赖性：13C固态核磁共振和红外光谱研究
作者：
A. Krushelnitsky;D. Faizullin;D. Reichert
固体聚L -赖氨酸的分子动力学已通过以下自然丰度13C - NMR弛豫方法进行了研究：测量弛豫时间T1在两个共振频率，非共振T1ρ在两个自旋锁频率，质子解耦T1ρ。实验在不同的温度和水合水平（高达17%的水重量）下进行。聚赖氨酸的天然丰度13C‐CPMAS光谱提供了所有类型的主链和侧链碳的光谱分辨率，因此可以分别确定每种类型的动态参数。同时，利用傅里叶红外光谱研究了聚赖氨酸的构象性质。采用相关函数形式和无模型方法对不同核磁共振实验获得的数据进行同步分析。结果表明，在干型聚赖氨酸中，主链和侧链参与了两次低振幅运动，相关时间分别为10−4 s和10−9 s。在水化过程中，除了较慢过程的振幅适度增加外，骨架的动态参数几乎保持不变。侧链动力学显示出更强的水化反应：慢速运动和快速运动的振幅都显著增加，慢速运动的相关时间缩短了约5个数量级，并且在水化水平超过10% H2O时，快速和慢速侧链运动在实验上无法区分。这些分子动力学的变化不能归因于任何水合作用依赖于聚赖氨酸的构象转变，因为红外光谱显示在主链或侧链吸收域几乎没有水合作用依赖。讨论了快、慢运动的物理性质、它们的相关时间分布以及微动力参数的水化依赖性。©2003 Wiley期刊公司生物工程学报（英文版），2004
The molecular dynamics of solid poly‐L‐lysine has been studied by the following natural abundance 13C‐NMR relaxation methods: measurements of the relaxation times T1 at two resonance frequencies, off‐resonance T1ρ at two spin‐lock frequencies, and proton‐decoupled T1ρ. Experiments were performed at different temperatures and hydration levels (up to 17% H2O by weight). The natural abundance 13C‐CPMAS spectrum of polylysine provides spectral resolution of all types of backbone and side chain carbons and thus, dynamic parameters could be determined separately for each of them. At the same time, the conformational properties of polylysine were investigated by Fourier transform infrared spectroscopy. The data obtained from the different NMR experiments were simultaneously analyzed using the correlation function formalism and model‐free approach. The results indicate that in dry polylysine both backbone and side chains take part in two low amplitude motions with correlation times of the order of 10−4 s and 10−9 s. Upon hydration, the dynamic parameters of the backbone remain almost constant except for the amplitude of the slower process that increases moderately. The side chain dynamics reveals a much stronger hydration response: the amplitudes of both slow and fast motions increase significantly and the correlation time of the slow motion shortens by about five orders of magnitude, and at hydration levels of more than 10% H2O fast and slow side chain motions are experimentally indistinguishable. These changes in the molecular dynamics cannot be ascribed to any hydration‐dependent conformational transitions of polylysine because IR spectra reveal almost no hydration dependence in either backbone or side chain absorption domains. The physical nature of the fast and slow motions, their correlation time distributions, and hydration dependence of microdynamic parameters are discussed. © 2003 Wiley Periodicals, Inc. Biopolymers 73: 1–15, 2004
影响因子：
2.9
作者：
Venyaminov, SY;Prendergast, FG
通讯作者：
Prendergast, FG