title: Interaction between bound water molecules and local protein structures: A statistical analysis of the hydrogen bond structures around bound water molecules.
abstract: Water molecules play an important role in protein folding and protein interactions through their structural association with proteins. Examples of such structural association can be found in protein crystal structures, and can often explain protein functionality in the context of structure. We herein report the systematic analysis of the local structures of proteins interacting with water molecules, and the characterization of their geometric features. We first examined the interaction of water molecules with a large local interaction environment by comparing the preference of water molecules in three regions, namely, the protein-protein interaction (PPI) interfaces, the crystal contact (CC) interfaces, and the non-interfacial regions. High preference of water molecules to the PPI and CC interfaces was found. In addition, the bound water on the PPI interface was more favorably associated with the complex interaction structure, implying that such water-mediated structures may participate in the shaping of the PPI interface. The pairwise water-mediated interaction was then investigated, and the water-mediated residue-residue interaction potential was derived. Subsequently, the types of polar atoms surrounding the water molecules were analyzed, and the preference of the hydrogen bond acceptor was observed. Furthermore, the geometries of the structures interacting with water were analyzed, and it was found that the major structure on the protein surface exhibited planar geometry rather than tetrahedral geometry. Several previously undiscovered characteristics of water-protein interactions were unfolded in this study, and are expected to lead to a better understanding of protein structure and function.
authors.forename: Seungpyo
authors.initials: S
authors.lastname: Hong
authors.affiliation: Department of Bio and Brain Engineering, KAIST, Daejeon, South Korea.
authors.forename: Dongsup
authors.initials: D
authors.lastname: Kim
mesh_terms: D016000:Cluster Analysis; D018360:Crystallography, X-Ray; D030562:Databases, Protein; D006860:Hydrogen Bonding; D008958:Models, Molecular; D011487:Protein Conformation; D017510:Protein Folding; D060066:Protein Interaction Maps; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism; D014867:Water / Q000737:chemistry* / Q000378:metabolism
chemical_list: D011506:Proteins; D014867:Water
keywords: interaction interface; protein folding; protein-water interaction; structural analysis; water interacting structure