Hydrophilic-hydrophobic interplay: from model systems to living systems

Water is a unique liquid, many of whose properties are critical for the continued support of life. In living systems, essential water-related phenomena occur in restricted geometries in cells, and at active sites of proteins and membranes or at their surface. The stability of biological systems is controlled by the subtle hydrophilic-hydrophobic interplay. It is well known that hydration water plays a prominent role in the relationship between structure, dynamics, and biological function. Various examples of systems developing either hydrophilic or hydrophobic interactions, or both, are presented. The static and transport properties of what is defined as confined or interfacial water are compared with those of bulk water. Finally, it is shown that there is some strong evidence that structural and dynamic properties of water close to a hydrophilic surface, at room temperature, are similar to that of bulk supercooled water. (C) 2004 Academie des sciences. Published by Elsevier SAS. All rights reserved.