Hydration and energy dissipation measurements of biomolecules on a piezoelectric quartz oscillator by admittance analyses
Hydration and energy dissipation measurements of biomolecules on a piezoelectric quartz oscillator by admittance analyses
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DOI：
10.1021/ac060873x
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发表时间：
2007-01-01
影响因子：
7.4
通讯作者：
Okahata, Yoshio
中科院分区：
文献类型：
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作者：
Ozeki, Tomomitsu;Morita, Mizuki;Okahata, Yoshio
通过使用与矢量网络分析仪连接的 27 MHz 压电石英振荡器，我们在水溶液中以及湿空气相中将生物素化牛血清白蛋白、生物素化 ssDNA、生物素化 dsDNA 和生物素化普鲁兰多糖与 NeutrAvidin 固定的 27 MHz 石英晶体微天平 (QCM) 板结合时，获得了共振频率降低 (-Delta F-water) 和能量耗散增加 (Delta D-water) （98% 湿度，-Delta F-湿和 Delta D-湿）和干燥空气相（-Delta F-空气和 Delta D-空气）。 -Delta F-水表示水溶液中分子、结合水和振动水的总质量。 -Delta F-wet 表示分子和结合水的总质量。 -Delta F-air 简单地显示 QCM 上分子的真实质量。就结果而言，(-Delta F-wet)/(-Delta F-air)值表明每单位生物分子质量的结合水比率的顺序为支链淀粉(2.1-2.2)>DNA=蛋白质(1.4-1.6)>聚苯乙烯(1.0)。 (-Delta F-水)/(-Delta F-空气)值表明每单位生物分子质量的流体动力水(结合水和振动水)比率的顺序为 dsDNA (6.5) > ssDNA = 普鲁兰多糖 (3.5-4.4) > 蛋白质 (2.4-2.5) > 聚苯乙烯 (1.0)。水中每单位质量的能量耗散参数（Delta D-水/（-Delta F-空气））的顺序为普鲁兰多糖> dsDNA> ssDNA>蛋白质>聚苯乙烯。湿空气相和干空气相（Delta D-wet 和 Delta D-air）中的能量耗散非常小，可以忽略不计，这表明即使这些生物分子在空气相（无水溶液）中也可充当弹性膜。我们在[(-Delta F-water)/(-Delta F-air) - 1]之间获得了良好的线性关系，这表明蛋白质的水合和Delta D-water/(-Delta F-air)。上述数值表明蛋白质的能量耗散主要是由水合引起的，并且蛋白质本身是弹性分子，在水溶液中不存在能量耗散。相反，变性蛋白质、DNA和普鲁兰多糖的情况相对偏离作为完美弹性材料的理论线的大量水合和能量耗散，这意味着除了由于分子水合导致的能量耗散之外，由于变性蛋白质、线性DNA和普鲁兰多糖在水相中的粘弹性特性而发生大量能量耗散。这两个参数可以表征水溶液中各种生物分子的结构特性。
By using a 27-MHz piezoelectric quartz oscillator connected with a vector network analyzer, we obtained resonance frequency decreases (-Delta F-water) and energy dissipation increases (Delta D-water) during binding of biotinylated bovine serum albumin, biotinylated ssDNA, biotinylated dsDNA, and biotinylated pullulan to a NeutrAvidin-immobilized 27-MHz quartz crystal microbalance (QCM) plate in aqueous solution, as well as in the wet air phase (98% humidity, -Delta F-wet and Delta D-wet) and in the dry air phase (-Delta F-air and Delta D-air). -Delta F-water indicates the total mass of the molecule, bound water, and vibrated water in aqueous solutions. -Delta F-wet indicates the total mass of the molecule and bound water. -Delta F-air simply shows the real mass of the molecule on the QCM. In terms of results, (-Delta F-wet)/(-Delta F-air) values indicated the bound water ratios per unit biomolecular mass were on the order of pullulan (2.1-2.2) > DNAs = proteins (1.4-1.6) > polystyrene (1.0). The (-Delta F-water)/(-Delta F-air) values indicated the hydrodynamic water (bound and vibrated water) ratios per unit biomolecular mass were on the order of dsDNA (6.5) > ssDNA = pullulan (3.5-4.4) > proteins (2.4-2.5) > polystyrene (1.0). Energy dissipation parameters per unit mass in water (Delta D-water/(-Delta F-air)) were on the order of pullulan > dsDNA > ssDNA > proteins > polystyrene. Energy dissipation in the wet and dry air phases (Delta D-wet and Delta D-air) were negligibly small, which indicates even these biomolecules act as elastic membranes in the air phase (without aqueous solution). We obtained a good linear relationship between [(-Delta F-water)/(-Delta F-air) - 1], which is indicative of hydration and Delta D-water/(-Delta F-air) of proteins. The aforementioned values suggest that the energy dissipation of proteins was mainly caused by hydration and that proteins themselves are elastic molecules without energy dissipation in aqueous solutions. On the contrary, plots in cases of denatured proteins, DNAs, and pullulans were relatively deviant toward the large hydration and energy dissipation from the theoretical line as perfect elastic materials, meaning that the large energy dissipation occurs because of viscoelastic properties of denatured proteins, linear DNAs, and pullulans in the water phase, in addition to energy dissipation due to the hydration of molecules. These two parameters could characterize various biomolecules with structural properties in aqueous solutions.