The relation between the Hofmeister anions and water structure at protein surfaces
2017 120th KCS Meeting
Water has unique properties based on hydrogen bonding that is come from the specific atomic composition and molecular structure of water. These properties are crucial for the survival of life on the Earth. Thus, researched for water is highly important. Specially, we focused on these properties of water with protein and ions. To understand the relation between them, we carried out a molecular dynamics (MD) simulation. The result revealed that an effect of protein can affect ion distribution as well as water network only near the protein surface. And, the order of water network disruption followed the order of the Hofmeister anion series which is related with solubility of protein. Investigation for structural change of protein didn't show any significant change in our simulation. So, this result suggests that changes in the properties of the protein could originate from the disruption of the water H-bond network induced by ions with a higher affinity for the protein surface instead of direct protein residue-ion interactions. Additional investigation for orientational distribution of water molecules shows slight preference for interfacial water molecules, i.e. a straddle structure, within short ranges from the protein surface. Lastly, we found out that the cation effect on water network is also not negligible at the protein surface.