Biological Water: Properties and Role in Muscle Function and Development

Thesis (Ph.D.)--University of Washington, 2014Water is the most abundant substance on planet Earth and present in large part of our daily lives. Despite such abundance, liquid water still remains mysterious for we do not understand its structure. Similarly, biological systems are largely composed of water and life is believed to have originated from water. However, the properties and functional role of biological water still remains an enigma. Thus, more wholesome understanding of biological water is needed to gain further purchase on workings of biological systems. The first part of this work was aimed at better understanding the properties of biological water. In biological systems, most of water is `interfacial'. Therefore, interfacial water near hydrophilic surface was characterized to model biological water. The results show that hydrophilic surfaces, including broad biological surfaces, can alter properties of nearby water extensively. These included increased viscosity, decreased kinetic energy, faster NMR spic-lattice (T1) relaxation and lower self-diffusion coefficient of water. The findings collectively indicate more ordered state of water near surfaces. In the second part of this work, water inside living muscle cells and intact myofibril was studied using molecular spectroscopy techniques. Both studies show that intracellular water within muscle has significantly stronger hydrogen bonding and hindered dynamics. In addition, changes in water properties have been correlated with muscle contraction and differentiation. Hence, water takes an active role at broad range of biological processes of varying time-scales