Functional Hydration Behavior: Interrelation between Hydration and Molecular Properties at Lipid Membrane Interfaces

Abstract

Water is an abundant commodity and has various important functions. It stabilizes the structure of biological macromolecules, controls biochemical activities, and regulates interfacial/intermolecular interactions. Common aspects of interfacial water can be obtained by overviewing fundamental functions and properties at different temporal and spatial scales. It is important to understand the hydrogen bonding and structural properties of water and to evaluate the individual molecular species having different hydration properties. Water molecules form hydrogen bonds with biomolecules and contribute to the adjustment of their properties, such as surface charge, hydrophilicity, and structural flexibility. In this review, the fundamental properties of water molecules and the methods used for the analyses of water dynamics are summarized. In particular, the interrelation between the hydration properties, determined by molecules, and the properties of molecules, determined by their hydration properties, are discussed using the lipid membrane as an example. Accordingly, interesting water functions are introduced that provide beneficial information in the fields of biochemistry, medicine, and food chemistry.

Naked Bacterium: Emerging Properties of a Surfome-Streamlined Pseudomonas putida Strain

“…In this case, particles of amphiphilic behavior are segregated from the solvent by increasing the ionic strength of the medium. Under this scenario, increasing the NaCl concentration fosters cell clumping by hydrophobic interactions, as the solvating power of the surface of the P. putida EM371 strain would not be strong enough to thermodynamically stabilize cells in solution and counteract this effect. − The practical consequence of all this is that surface-naked cells can be made more or less stable in suspension by manipulating salt contents of the growth media.…”

Effect of H3O+ on the Structure and Dynamics of Water at the Interface with Phospholipid Bilayers

“…For example, the pK a of 0.8 was determined by assuming that the APL is constant and corresponded to that of a fluidphase phosphatidylcholine bilayer, and that the dielectric permittivity and other properties of the interfacial water are the same as those of bulk water 60 . There are numerous wetlab and computational studies showing that interfacial water clearly deviates from that of bulk water [3][4][5][6][7] and variations in pH induce phase transitions in lipid bilayers and alter APL 35 . Finally, our study was aimed understanding what happens to properties of water when the membrane is altered by the presence of H 3 O + ions at the water-lipid interface, rather that understanding the process of protonation or deprotonation, which cannot be described by classical MD.…”

“…Rather than being a mere solvent driving the hydrophobic effect, water at the water-lipid interface should be "considered as a component of the membrane" that acts a "connecting material" affecting the structure and thus function of membranes 2 . The structure and dynamics of such interfacial water has been studied using a wide range of techniques [3][4][5][6][7] . The combined results from these studies suggest that interfacial water has distinct properties that differ from the ones of bulk water.…”

Hydration Dynamics in Biological Membranes: Emerging Applications of Terahertz Spectroscopy

“…This inherent plasticity in water structure is manifested in the broad temporal scale characteristic of hydration dynamics, spanning at least 9 orders of magnitude (Figure ). Intra- and inter-molecular dynamics of water in the molecular length scale, including O–H bond stretching/bending, librational motion and hydrogen-bond fluctuation/reorganization, are relatively well-studied and known to occur in the femtosecond to subpicosecond time scale. − Although insights into these modes of hydration dynamics originate predominantly from studies of bulk water, picosecond orientational dynamics has been recently reported for water in live cells. , Additional dynamic processes occurring in this time scale, albeit at a possibly longer length scale, include proton transfer and translational diffusion . The other end of this spectrum is populated by several collective modes of hydration dynamics characterized by a subnanosecond to microsecond time scale.…”