The structure of aqueous guanidinium chloride solutions
The structure of aqueous guanidinium chloride solutions
复制标题
DOI：
10.1021/ja040034x
复制
发表时间：
2004-09-22
影响因子：
15
通讯作者：
Brady, JW
中科院分区：
文献类型：
--
作者：
Mason, PE;Neilson, GW;Brady, JW
结合中子衍射与同位素取代（NDIS）实验和分子动力学（MD）模拟来表征变性剂氯化胍水溶液中的结构。模拟和实验在室温下以3 m的浓度进行，允许在现实溶液环境中检查任何离子结合的倾向。模拟令人满意地再现了中子散射的主要特征，并表明了胍离子的双峰水化，N-H基团在分子平面上形成有序的氢键，但在平面上相对缺乏与水的相互作用。这些溶液最显著的特点是在模拟中观察到在胍离子周围有丰富的离子-离子顺序。胍离子与缺乏水的表面平行堆叠的明显趋势表明，这种离子作为变性剂的效率是由于它能够同时与蛋白质的水和疏水侧链有利地相互作用。
The combination of neutron diffraction with isotopic substitution (NDIS) experiments and molecular dynamics (MD) simulations to characterize the structuring in an aqueous solution of the denaturant guanidinium chloride is described. The simulations and experiments were carried out at a concentration of 3 m at room temperature, allowing for an examination of any propensity for ion association in a realistic solution environment. The simulations satisfactorily reproduced the principal features of the neutron scattering and indicate a bimodal hydration of the guanidinium ions, with the N-H groups making well-ordered hydrogen bonds in the molecular plane, but with the planar faces relatively deficient in interactions with water. The most striking feature of these solutions is the rich ion-ion ordering observed around the guanidinium ion in the simulations. The marked tendency of the guanidinium ions to stack parallel to their water-deficient surfaces indicates that the efficiency of this ion as a denaturant is due to its ability to simultaneously interact favorably with both water and hydrophobic side chains of proteins.