Nonequilibrium Responses of Complex Fluids and Proteins to Nano-mechanical Perturbation

Jelena Pesic
University of Chicago

Tuesday, October 12, 2010 at 1:00pm
Engr IV Maxwell Room 57-124

Abstract

We use optical trapping experiments, Stokesian Dynamics, and Steered Molecular Dynamics simulations to study the nonequilibrium responses of complex fluids and proteins to mechanical perturbation. We study the coupling of an optically driven colloid particle to a monodisperse quasi-two-dimensional (q2d) colloid bath to elucidate the structural fluctuations in nonequilibrium and the effects of the colloid packing and close confinement. Dynamics is characterized via temporal fluctuations of order parameters that define the system properties in the immediate proximity to and away from the trapped colloid. We transition from statistical mechanics of mesoscopic colloidal fluids to that of complex molecular systems. Photoactive Yellow Protein (PYP) is used as a model system to study anisotropic protein response to mechanical unfolding along two different protein axes. A reconstruction of Potential of Mean Force (PMF) is obtained using the Jarzynski Equality and the Fluctuation Theorem along different reaction coordinates.