Hydration Study of Globular Proteins by Microwave Dielectric Spectroscopy
Hydration Study of Globular Proteins by Microwave Dielectric Spectroscopy
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DOI：
10.1021/jp011217y
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发表时间：
2001-11
影响因子：
3.3
通讯作者：
K. Yokoyama;T. Kamei;and Hiroshi Minami;Makoto Suzuki
中科院分区：
文献类型：
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作者：
K. Yokoyama;T. Kamei;and Hiroshi Minami;Makoto Suzuki
利用相对介电常数在2~10 GHz范围内误差为0.02的高重复性精密网络分析仪，对蛋白质在溶液中的水化特性进行了微波介电测量。在20.0±0.01℃下测定了过氧化氢酶、胰凝乳酶原A、细胞色素C、血红蛋白、过氧化物酶、溶菌酶、肌红蛋白、卵清蛋白和牛血清白蛋白。在上述频率范围内，基于Wagner混合理论和对水化溶质复介电常数的一次德拜近似，对蛋白质分子的水化性能进行了评估。这是用来计算由单一的德拜拟合得到的松散结合水数NW，它给出了松散结合水化壳和紧密结合水化水数NS的松弛频率(FC)，其松弛频率比FC低。将这些水化数与疏水原子和亲水暴露原子可达的单层水数进行了比较，结果表明，这些水化数比疏水原子和亲水原子的水化数大。
A microwave dielectric measurement was performed to study the hydration properties of proteins in solution with a precision network analyzer with high reproducibility within the errors of 0.02 in relative dielectric constant over 2 to 10 GHz. A measurement was carried out for catalase, chymotrypsinogen A, cytochrome C, hemoglobin, peroxidase, lysozyme, myoglobin, ovalbumin, and bovine serum albumin at 20.0 ± 0.01 °C. The hydration properties of protein molecules were evaluated based on the Wagner mixture theory combined with single Debye approximation to the complex dielectric constant of hydrated solutes in the above frequency range. This was used to evaluate the loosely bound water number Nw from the single Debye fitting, which gives the relaxation frequency (fc) of the hydration shell loosely bound and tightly bound water number Ns with lower relaxation frequencies than fc. Those hydration numbers were compared with the monolayer water numbers accessible to hydrophobic and hydrophilic exposed atoms, re...