Conformation relaxation dynamics of biomolecules

Title: Conformational Relaxation Dynamics of Biomolecules

Speaker: Robert D. Young, Northern Arizona University, Flagstaff AZ

Abstract: A model of conformational relaxation dynamics in hydrated biomolecules and possibly glass-forming liquids is developed using data from a range of experimental tools including dielectric, NMR, Mössbauer, and neutron scattering. The model is based on two crucial features: 1) Hydration layer and bulk solvent fluctuations drive major protein fluctuations; 2) The probability density for relevant fluctuations in the hydration layer of a protein or in the bulk solvent is measured in dielectric or NMR relaxation spectra. The temperature behavior of the conformational mean-square displacement from a quasielastic neutron scattering experiment is shown to have a clear physical origin in the temperature-shifting distribution of relaxation rates for the appropriate fluctuation phenomena and the fixed time window of the experiment. Results show that proposed “dynamical transitions”, including fragile-to-strong crossover, are not supported physical properties of hydrated proteins.