Speaker : Professor Michael L. Klein, FRS, Laura H Carnell Professor of Science, Dean of Science & Technology, Temple University, Philadelphia PA 19122 USA.
Title : "Wetting-Dewetting Transitions & Nature’s Exquisite Sensing Machines: Unveiling the Molecular Mechanism of Pain?"
Abstract: Everyday experience tells us that water will not “wet” an oily surface. For example, when rain falls on a car that has been recently cleaned and waxed, the rainwater forms droplets and does not wet the surface as a continuous film. This talk will explore the microscopic manifestations of this phenomenon as it applies to naturally occurring and engineered surfaces, comprised of molecules. Of particular interest are so-called ion channels that are Nature’s way of allowing communication between the inside and outside of the cell. Ion channels live in the lipid bilayer membrane that is the main constituent of the cell wall. Typically, ion channels consist of a bundle of a few proteins organized around a central pore, through which ions such as sodium and potassium, either enter or leave the cell.
Membrane-bound ion channels often have a common structural motif, consisting of the central pore, plus so-called peripheral sensor domains that control opening and/or closing (gating) of the pore to allow passage of ions into or out of the cell. The latter, in turn, provide the control mechanisms for many physiological functions. The overall architecture of sodium and potassium ion channels, is shared with other ion channels, such as the so- called transient receptor potential (TRP) family of sensory channels. Structural studies on ion channels over the past few years have yielded clues into the possible operational mechanisms of Nature’s nanomachines, including members of the TRP family.
After a general discussion on the phenomenon of wetting and dewetting, this presentation will focus on one specific ion channel, the so-called capsaicin or vanilloid receptor, TRPV1, which promotes the passage of ions across cellular membranes in response to stimuli such as acidity and hotness. Importantly, the molecular underpinnings of TRPV1 gating, in particular the mechanism, is still unclear. Here, large-scale molecular dynamics simulations have been employed in an attempt to shed light on the closed to open gating transition of TRPV1. Seemingly, gating relies on the motion of a single, evolutionarily conserved, amino acid in the region of the pore domain. A model for TRPV1 gating is proposed, based on the molecular simulations.
About the speaker: Prof. Michael Klein’s research interests are focused on use of theoretical & computational methodologies to study of solids, liquids & assemblies of macromolecules. Over the past five decades, he developed methodologies and carried out computer simulations to understand the dynamical behavior of molecular solids and liquids, including water, the phase behavior of surfactants & lipids, and the dynamics of natural & synthetic self-assembling macromolecules. He leads a team of computational scientists dedicated to the understanding materials properties, while at the same time developing methodologies that are used by other computational scientists worldwide. As Dean of Science & Technology, he is actively working on transitioning Science & Technology at Temple (“Philadelphia’s Public University”) into a leading research institution that performs theoretical, experimental, and computational research in multiple fields of science. Prof. Klein is passionate about undergraduate research as well as supporting sustainable community engagement activities for the City of Philadelphia and more broadly regionally and nationally.