Research

Water interfacial chemistry at solid hydroxylated silica surface

The main theme of this work is to understand water dynamics at the solid-liquid interface. The solid interface (bare hydroxylated silica surface or grafted with differnt kind of hydrophobic chain) perturbs the static, dynamics and vibrational features of water molecules. Water molecules tend to have preferred orientation, physical adsoprtion at hydroxy -OH group of the silica layer. In the presence of hydrophobic chains and co-solvent (methanol or acetonitrile) these structuring are partially broken and water molecules are exchanged with co-solvent showing competing behavior.

Water dynamics at dimeric protein interface coupled with protein internal and external motion

It has been known since long how water molecules at dimeric interface of Scapharca Hemoglobin plays a key role in the allosteric behavior of protein. The present research work is oriented towards the cross communication between protein monomers in terms of ligand binding and water dynamics at the interface. The experimental data shows that allosteric properties have underlying tertairy change unlike human hemolglobin. The overall time scale for protein structural change is around 80 mus. However the present work explicity finds strutural changes occuring on the time scale of ns. These structural changes include flipping of the side chain dihedral angle of Phe97 residue, which is one of the structral differences found between deoxy and oxy state. The other change is the water migration from the dimeric interface to the distal site where ligand binds and migration of CO ligand to the solvent through Xe4 pocket which was speculated in other previous studies. These finding clearly shows the coupled dynamics between Phe97 flipping and change in the number of water molecules at the interface.