NMR Seminar November 5 Professor Song-i Han (hosted by Conradi) Department of Chemistry and Biochemistry, University of California Santa Barbara Hyperpolarized Water as a Probing Tool for Molecular Interaction My group has developed a unique instrumental and methodological approach, based on employing Overhauser dynamic nuclear polarization (DNP), to achieve the selective 1H nuclear magnetic resonance signal amplification of only interfacial hydration water within 2-10 Å molecular length scales of spin-labeled biomolecular systems, including proteins and lipid membranes. Key features of our technique include the access to segment-specificity, the access to surface as well as internal / buried protein sites, and that there is no size limitation to the protein or molecular assembly to be analyzed. Significant signal amplification achieved through the Overhauser DNP effect provided us with unprecedented sensitivity for detecting surface and interfacial hydration dynamics of spin labeled molecules under ambient conditions, in dilute solutions, and of minute quantities. Hydration water is essential to protein function, and moreover, the local profile of protein hydration dynamics at the segment-specific level is thought to guide the binding, folding, aggregating or signaling process of proteins. I will demonstrate that the capability to measure local water dynamics at specific protein sites can serve to probe a wide range of biomolecular events. Our studies include the characterization of the initiation and early aggregation events of tau proteins, the hydrophobic collapse in apomyoglobin folding and the state of water on the surface and within the bilayers of lipid membranes. Lecture: 3:00 PM, 241 Compton