Atomic-scale Characterisation of Dielectric Properties and Structured Water Molecules at the Interface of Lipid Membranes

Water molecules play a major role in determining the structure and function of biomolecules and their assembly. Hydration layers occurring at the interface of macromolecules strongly depend on their molecular charge distribution and dielectric polarization, which in turn determine their electrostatic and electrodynamic properties. At a greater scale, water molecules surrounding and permeating the cell membrane have been demonstrated organising on the cell membrane components themselves, i.e. lipids and transmembrane proteins. For instance, evidences showed that lipid head groups are supposed to be surrounded by more than one hydration layer, being the first layer formed by a tightly bound shell, and outer layers likely to be displaced due to protein-lipid interactions. Hence, it is of fundamental importance to understand the physical properties of interfacial water in order to gain information on the structure and function of biological systems.