Thermal properties and hydration structure of poly-l-lysine, polyglycine, and lysozyme
Thermal properties and hydration structure of poly-l-lysine, polyglycine, and lysozyme
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DOI：
10.1016/j.molliq.2015.08.048
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发表时间：
2016-05
影响因子：
6
通讯作者：
K. Yoshida;A. Tashiro;T. Yamaguchi
中科院分区：
文献类型：
--
作者：
K. Yoshida;A. Tashiro;T. Yamaguchi
采用差示扫描量热法（DSC）和x射线衍射（XRD）对水合水平（水质量/肽和蛋白质量）分别为0.30 ~ 0.82、0.27 ~ 0.49和0.30 ~ 0.81时的聚赖氨酸、聚甘氨酸和溶菌酶进行了测定，温度范围为180 ~ 298 K。DSC数据表明，即使在180k下，多肽和蛋白质的界面水化水也没有冻结。x射线径向分布函数显示，随着温度的降低，多肽和蛋白质与水合水分子的相互作用逐渐显著，导致其水合水结构的发展。随着温度的降低，水合水的结构变化是单调的，不可能是先前中子散射观察到的水合蛋白动态转变（玻璃化转变和弱-强交叉）的起源。
Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) measurements of hydrated poly-l-lysine, polyglycine and lysozyme at hydration levels (mass of water/mass of peptide and protein) = 0.30–0.82, 0.27–0.49, and 0.30–0.81, respectively, were performed in the temperature range of 180–298 K. The DSC data showed that the interfacial hydration water of the polypeptides and the protein is not frozen even at 180 K. The X-ray radial distribution functions revealed that with decreasing temperature the interactions of the polypeptides and the protein with hydration water molecules gradually become remarkable, resulting in the development of the structure of their hydration water. The structure change of the hydration water with lowering temperature is monotonous and could not be the origin of dynamic transition (glass transition and fragile-to-strong crossover) for hydrated proteins as previously observed by neutron scattering.