Hédoux A, Willart J-F, Ionov R, Affouard F, Guinet Y, Paccou L, Lerbret A, Descamps M
Laboratoire de Dynamique et Structure des Matériaux Moléculaires, UMR CNRS 8024, Université de Lille 1, UFR de Physique, Bat. P5, 59 655 Villeneuve d'Ascq Cedex, France.
J Phys Chem B. 2006 Nov 16;110(45):22886-93. doi: 10.1021/jp061568i.
Sugar-induced thermostabilization of lysozyme was analyzed by Raman scattering and modulated differential scanning calorimetry investigations, for three disaccharides (maltose, sucrose, and trehalose) characterized by the same chemical formula (C(12)H(22)O(11)). This study shows that trehalose is the most effective in stabilizing the folded secondary structure of the protein. The influence of sugars on the mechanism of thermal denaturation was carefully investigated by Raman scattering experiments carried out both in the low-frequency range and in the amide I band region. It was determined that the thermal stability of the hydrogen-bond network of water, highly dependent on the presence of sugars, contributes to the stabilization of the native tertiary structure and inhibits the first stage of denaturation, that is, the transformation of the tertiary structure into a highly flexible state with intact secondary structure. It was found that trehalose exhibits exceptional capabilities to distort the tetra-bonded hydrogen-bond network of water and to strengthen intermolecular O-H interactions responsible for the stability of the tertiary structure. Trehalose was also observed to be the best stabilizer of the folded secondary structure, in the transient tertiary structure, leading to a high-temperature shift of the unfolding process (the second stage of denaturation). This was interpreted from the consideration that the transient tertiary structure is less flexible and inhibits the solvent accessibility around the hydrophobic groups of lysozyme.
通过拉曼散射和调制差示扫描量热法研究，对三种化学式相同（C(12)H(22)O(11)）的二糖（麦芽糖、蔗糖和海藻糖）诱导溶菌酶热稳定性进行了分析。本研究表明，海藻糖在稳定蛋白质折叠二级结构方面最为有效。通过在低频范围和酰胺I带区域进行的拉曼散射实验，仔细研究了糖类对热变性机制的影响。已确定，高度依赖糖类存在的水的氢键网络的热稳定性有助于天然三级结构的稳定，并抑制变性的第一阶段，即三级结构转变为具有完整二级结构的高度柔性状态。发现海藻糖具有非凡的能力来扭曲水的四键氢键网络，并加强负责三级结构稳定性的分子间O-H相互作用。还观察到海藻糖是折叠二级结构在瞬态三级结构中的最佳稳定剂，导致去折叠过程（变性的第二阶段）的高温偏移。这是从瞬态三级结构较不灵活且抑制溶菌酶疏水基团周围溶剂可及性的角度来解释的。
