Frontier Research Institute for Interdisciplinary Sciences
Tohoku University

Biomolecules such as proteins and nucleotides have high degrees of freedom in their molecular structures which realize the biological functions. By recent physicochemical studies, energetic importance of interactions between a biomolecule and the surrounding water molecules has been recognized in the hydration and large conformational changes of protein. In other words, a biomolecule and the surrounding water molecules exhibit a biological function cooperatively as an assembly. For understanding the dynamics of biomolecular systems, it is essential to analyze the behavior of the biomolecule-water assembly combining with the energetic calculations. In this study, we have detected large changes in the hydration properties of restrained water and hypermobile water molecules around an actin filament corresponding to the structural change by replacing ionic and nucleotide species. Collaborating with theoretical scientists of molecular dynamics, statistical mechanics and quantum mechanics, we are constructing advanced energetics of biomolecular machinery systems and finding the local extent over 1 nm of hypermobile water layer formed around a metallic ion and the physical origin of hypermobile water. In future, we plan to realize a molecular linear-motor by driving a protein along a protein filament as shown in Figure 1.