Structural properties of water confined by phospholipid membranes

作     者：Fausto Martelli Hsin-Yu Ko Carles Calero Borallo Giancarlo Franzese 

作者机构：Department of Chemistry Princeton University Princeton NJ 08544 USA Seccio de Fisica Estadlstica i Interdisciplinaria-Departament de Fisica de la Materia CondensadaFacultat de Fisica Universitat de -Barcelona Mart i Franqus 1 08028 Barcelona Spain Institute of Nanoscience and Nanotechnology (IN2UB) Universitat de Barcelona Av. Joan XXIII S/N 08028 Barcelona Spain 

出 版 物：《Frontiers of physics》 (物理学前沿（英文版）)

年 卷 期：2018年第13卷第1期

页      面：57-64页

核心收录：

学科分类：07[理学] 08[工学] 071102[理学-系统分析与集成] 0711[理学-系统科学] 081104[工学-模式识别与智能系统] 081402[工学-结构工程] 081304[工学-建筑技术科学] 0813[工学-建筑学] 0704[理学-天文学] 0814[工学-土木工程] 0811[工学-控制科学与工程] 0702[理学-物理学] 081103[工学-系统工程] 

基　　金：Spanish Ministry of Economy and Knowledge (MINECO) the European Fund for Regional Development (FEDER) the Barcelona Supercomputing Center 

主　　题：confined water dimyristoylphosphatidylcholines DMPC order parameter 

摘      要：Biological membranes are essential for cell life and hydration. Water provides the driving force for the assembly and stability of many cell components. Here, we study the structural properties of water in a phospholipid membrane. We characterize the local structures, inspecting the intermediate range order （IRO） and adopting a sensitive local order metric recently proposed by Martelli et al. that measures and grades the degree of overlap of the local environment with the structures of perfect ice. Close to the membrane, water acquires a high IRO and changes its dynamical properties; i.e., its translational and rotational degrees of freedom slow in a region that extends over - 1 nm from the membrane interface. Surprisingly, we show that at distances as far as -~ 2.5 mn from the interface, although the bulk-like dynamics are recovered, the IRO of water is still slightly higher than that in the bulk under the same thermodynamic conditions. Therefore, the water-membrane interface has a structural effect at ambient conditions that propagates further than the often-invoked 1-nm length scale. Consequently, this should be considered when analyzing experimental data of water confined by membranes and could help us to understand the role of water in biological systems.