Dielectric relaxation of aqueous solutions of ribonuclease A in the absence and presence of urea
Dielectric relaxation of aqueous solutions of ribonuclease A in the absence and presence of urea
复制标题
在不存在和存在尿素的情况下核糖核酸酶 A 水溶液的介电弛豫
DOI：
10.1002/bbpc.19971011219
复制
发表时间：
1997
影响因子：
4.8
通讯作者：
M. Stockhausen
中科院分区：
文献类型：
--
作者：
T. Abou;U. Becker;R. Biedenkap;R. Brengelmann;R. Elsebrock;H. Hinz;M. Stockhausen
在20°C下，在纯水和8 mol/l尿素溶液两种溶剂中，在2 MHz ~ 72 GHz的频率范围内，测量了核糖核酸酶A（RNase）水溶液的介电谱。这些环境条件分别促进蛋白质的天然和未折叠状态。结果进行了讨论，关于（i）的低和（ii）的频谱的高频部分。对（i）的贡献可归因于RNA酶的翻滚运动，尿素的存在改变了这种贡献，表明RNA酶部分的极性增加了，但大小并不显著。从（ii）可以得出结论，尿素的加入导致整体水结构和动力学的变化，这是伴随着增加的分数的非缔合溶剂分子。这些可能在变性过程中起作用。
The dielectric spectra of aqueous solutions of ribonuclease A (RNase) have been measured in the frequency domain over the whole absorption region between 2 MHz and 72 GHz at 20°C in two solvents, pure water and 8 mol/1 urea solution. These environmental conditions promote the native and unfolded state of the protein, respectively. The results are discussed with regard to (i) the low and (ii) the high frequency part of the spectra. The contribution to (i) which is attributable to the tumbling motion of RNase is changed by the presence of urea, indicating that the RNase moieties are increased in polarity, but only insignificantly in size. From (ii) it is concluded that addition of urea leads to a change in the overall water structure and dynamics which is accompanied by an increased fraction of non-associated solvent molecules. These are likely to be instrumental in the denaturation process.