Confined Protein Hydration & Dynamics

University Of Pennsylvania, Philadelphia PA

Investigators

Abstract

Intellectual Merit: Proteins perform the majority of functional tasks in living systems and to do so they must be dynamic. Internal protein motion is well known to be dependent on the solvation environment. Though the interaction between solvent water and protein has been extensively studied computationally, site-resolved experimentally derived information on this critical interaction is severely lacking. This project will help to fill this void by quantitatively describing the hydration and dynamics of model proteins under nanoconfined conditions. Both specific water-protein interactions and bulk solvation properties have critical effects on protein structure and function. Solvation conditions under nanoconfinement are now known to differ considerably from bulk solvation, raising the question of how the altered solvation environment in the tight spaces of the cell affects protein behavior. Reverse micelles have become a primary model for studying physicochemical properties of nanoconfined species. Over the past decade, reverse micelle encapsulation has also been adapted for the structural study of proteins using high-resolution NMR. This project will take advantage of the favorable properties of the reverse micelle system to answer fundamental questions of how confinement alters protein hydration and dynamics. Advanced NMR methods will be employed to characterize the effects of confinement on the picosecond-nanosecond-microsecond-millisecond time scales. Hydration waters will be detected and characterized also using NMR-based methods. The data yielded by these studies will permit analysis of the correlations between protein structural character, hydration properties, and protein motion. Such data will help fill the gap between theory and experiment in the exploration of the protein-solvent dynamic landscape. Broader Impacts: The project will be carried out in a laboratory that has a long history of involving undergraduate, graduate and postdoctoral trainees in cutting edge research. In addition, personnel affiliated with this project are engaged in the NSF SPARK program in Philadelphia. SPARK is designed to nurture the participation of under-represented minorities in the sciences. The results of the research project will be disseminated in high profile journals providing significant exposure not only for the scientific product itself but also for those who have generated it. Finally, the project rests on an emerging technology NMR spectroscopy of encapsulated proteins in low viscosity fluids - and will illustrate the utility and capabilities of this approach thereby continuing to bring a new and innovative technology to the biophysical community. This project is jointly supported by the Molecular Biophysics Program in the Division of Molecular and Cellular Biosciences and the Experimental Physical Chemistry Program in the Chemistry Division.