New experimental techniques such as wide-angle neutron and quasi-elastic neutron scattering, third generation x-ray synchrotrons, accompanied by interpretation and analysis using molecular dynamics, have emerged for characterizing the structure and dynamics of complicated solvent environments near biological macromolecules and interfaces. How these solvents and co-solvents influence protein function or mediate protein-protein interactions have numerous connections to our understanding of the fundamental aspects of cellular function, self-assembly in bio-inspired nanomaterials and in high-throughput protein technologies and bioprocessing. Unfortunately, experimental studies of solvent influences on self-assembly and organization have been relatively rare and not systematic. One of the principal limitations is that techniques able to investigate solution organization or solvation dynamics give highly averaged information over all different kinds of molecular interactions, with a variety of time scales and length scales. To address these limitations, we have developed a well-defined model system based on amino acid monomers in solution that permits us to dissect interactions over nanometer length scales and picosecond time scales. This model system investigates the evolution of solution structure and dynamics by varying amino acid concentration, thereby modeling how the solvent behaves under dissociating conditions when the local concentration of amino acids is relatively dilute, while more concentrated solutions describe the consequences of hydration near assembled solute states or at protein-protein interfaces when the local concentration of amino acids is very high. In this talk I will place our QENS measurements on model biological solutes in the context of other spectroscopic techniques, and provide both confirming as well as complementary dynamical information that attempts to give a unifying molecular view of hydration dynamics signatures near peptides and proteins.
OGG -INFM/CRS SOFT Grenoble