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Title: FROM TRANSITIONS IN ICE POLYMORPHS TO SLAVING OF PROTEIN DYNAMICS AND, TO INSULIN DIMER DISSOCIATION: THE MAGICAL WORLD OF WATER
Date and Time: Wednesday 16th September 2020 at 4 pm
Venue: Microsoft Teams (link will be updated when available)

Abstract:
For a simple molecule consisting of only of one oxygen and two hydrogen atoms, water exhibits enormous diversity, starting from an intricate phase diagram in the solid phase with many polymorphs, to controlling life on planet earth and probably elsewhere. Importantly, the role of water in biology is getting increasing focus on the microscopic details, such as the role of water in protein association-dissociation reactions, and dynamics of antibody-antigen complex. Here we shall discuss (within the limited time) a few of such problems which nevertheless are quite general in nature.We shall address the issue of the origin — the topological versus energetic factors — that could lead to the existence of the large number of crystalline and amorphous forms of ice, each with distinct properties.These phasesareof great importance for many reasons, including their presence in the intergalactic matter, and in glaciers, under high pressure. Here we attempt to develop a molecular level understanding of the nature of these transitions with an emphasis on the structural and thermodynamic aspects. Next, we discuss water in biological systems like therole of water in slaving protein dynamics (the Frauenfelder hypothesis), water in insulin dimer dissociation, and also water undernanoconfinements. Water is found to play critical role in all these processes. We offer a microscopic understanding of Fraunfelder’s “Water Slaving Protein Motion” hypothesis, via an interesting 1/f noise in the protein-water interaction energy spectrum. Our protein dimer dissociation and nanoconfined water studies reveal that water could be dynamically correlated over a large length scale due its extensive hydrogen bond network. The emphasis shall be on understanding these phenomena from a microscopic aspect.