arXivDaily arXiv每日学术速递 周一至周五更新
北美退伍军人节(Veterans Day),12 日无更新
arXiv 1202.3043cond-mat.softphysics.bio-ph
收藏

蛋白质溶液弛豫动力学的介电谱研究

Relaxation dynamics of a protein solution investigated by dielectric spectroscopy

M. Wolf, R. Gulich, P. Lunkenheimer, A. Loidl

摘要:

在目前的工作中,我们提供了两个不同浓度的溶菌酶水溶液的介电研究的频率范围从1 MHz到40 GHz和温度从275到330 K。我们分析了三个分散区,通常发现在蛋白质溶液中,通常被称为β-,γ-和δ-松弛。β-弛豫,发生在频率范围约10 MHz和γ-弛豫约20 GHz(在室温下),可以归因于极性蛋白质分子在其水介质中的旋转和自由水分子的重新取向运动,分别。δ松弛的本质,这往往是归因于结合水分子的运动,尚未完全理解。在这里,我们提供的数据的弛豫时间和弛豫强度的所有三个检测过程的温度依赖性和离子电荷传输所产生的直流电导率。β-和γ-弛豫的温度依赖性密切相关。我们发现了一个显着的温度依赖性的蛋白质的偶极矩,表明构象的变化。此外,我们发现在这种蛋白质溶液中Debye-Stokes-Einstein关系的破裂,即,DC电导率不完全由溶剂分子的迁移率控制。相反,它似乎是直流电导率密切相关的水化壳动力学。

英文摘要:

In the present work, we provide a dielectric study on two differently concentrated aqueous lysozyme solutions in the frequency range from 1 MHz to 40 GHz and for temperatures from 275 to 330 K. We analyze the three dispersion regions, commonly found in protein solutions, usually termed beta-, gamma-, and delta-relaxation. The beta-relaxation, occurring in the frequency range around 10 MHz and the gamma-relaxation around 20 GHz (at room temperature) can be attributed to the rotation of the polar protein molecules in their aqueous medium and the reorientational motion of the free water molecules, respectively. The nature of the delta-relaxation, which often is ascribed to the motion of bound water molecules, is not yet fully understood. Here we provide data on the temperature dependence of the relaxation times and relaxation strengths of all three detected processes and on the dc conductivity arising from ionic charge transport. The temperature dependences of the beta- and gamma-relaxations are closely correlated. We found a significant temperature dependence of the dipole moment of the protein, indicating conformational changes. Moreover we find a breakdown of the Debye-Stokes-Einstein relation in this protein solution, i.e., the dc conductivity is not completely governed by the mobility of the solvent molecules. Instead it seems that the dc conductivity is closely connected to the hydration shell dynamics.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑