Charla: Nano-Rheology: a novel method to study molecular dynamics

Charla: Nano-Rheology: a novel method to study molecular dynamics

Faculty of Chemical and Pharmaceutical Sciences, Department of Biochemistry and Molecular Biology, University of Chile.

Dr. Zahra Alavi, Assistant Professor, Department of Physics, Loyola Marymount University, Los Angeles, California, USA

Tuesday 5 April at 11.30 hrs.

Hybrid format

Face-to-face room 6, Aulario Facultad de Ciencias Químicas y Farmacéuticas, Dr. Carlos Tobar 964, Independencia, Santiago, Chile (those who come in person, show poster and mobility pass when entering the faculty)

Zoom coordinates will appear in the networks of the Faculty, quimica.uchile.cl, www.instagram.com, www.Facebook.com or request Ruth Tapia (rtapia@ciq.uchile.cl)

Language: English (questions can be asked in Spanish, English and Farsi)

Summary:

Microscopic mechanisms of friction, the relation between dissipation and nonlinearity, nonequilibrium processes in nanoscale systems, are all incompletely understood, funda- mental, interconnected problems in nanoscience. These topics appear with experimental immediacy when probing enzyme mechanics by nanorheology. Using the unique capability of measuring directly dissipation occurring in the driven deformation of folded enzyme molecules, this project investigates the origin of this molecular scale friction, specifically the contribution of the surface of the molecule, which includes the hydration layer. Hydration layer dynamics, explored by nanorheology, is also the starting point of a new, dynamic understanding of kosmotropic (order inducing) and chaotropic agents, a physical chemistry topic which this research develops. Finally, the project explores the possibility of light emission from dynamically stressed molecules, with the aim of developing a new spectroscopy to characterize dissipation at the molecular scale. Nano-rheology allows the measurement of the stress–strain relations for a folded, native enzyme with sub-A resolution and at different frequencies. Through recent improvements, the method now allows accurate measurements of the phase of the mechanical response, as well as the amplitude, and thus gives direct access to the dissipation. This project focuses on the dissipative part of the dynamics, which is the nonlinear but reversible mechanical regime of large amplitude deformations for these molecules.