Professor Wompil Im
Department of Molecular Biosciences and Center for Bioinformatics
The University of Kansas
Lawrence KS

Monday, January 24, 2011
3:00 pm (CT)
3269 Beckman Institute

Abstract

Understanding the delicate balance of forces governing helix/β-hairpin interactions in transmembrane proteins is central to understanding membrane structure and function. These membrane constituent interactions play an essential role in determining the structure and function of membrane proteins, and protein interactions in membranes, and thus form the basis for many vital processes, including transmembrane signaling, transport of ions and small molecules, energy transduction, and cell-cell recognition. “Why does a single transmembrane helix or β-hairpin have specific orientations in membranes?” “What are the roles of hydrogen bonds, close packing, and helix-lipid or β- hairpin-lipid interactions in helix or β-hairpin associations in membranes?” “How do these interactions change the membrane structures?” “How do transmembrane domains transmit signals across membranes?” These are fundamentally important biophysical questions that can be addressed by understanding the delicate balance of forces governing helix/β-hairpin interactions in membranes. Recently, we has published novel methods and their applications that begin to address the complicated energetics and molecular mechanisms of these interactions at the atomic level by calculating the potentials of mean force (PMFs) along reaction coordinates relevant to helix/β- hairpin motions in membranes, and dissecting the total PMF into the contributions arising from physically important microscopic forces. I will summarize our research accomplishment so far, and present recent on-going research activities to elucidate aforementioned questions. If time allows, I will briefly mention about other research activities in my lab, such as the CHARMM-GUI development including a recent development of Glycan Reader, non-protein membrane simulation results, and protein translocation through the bacterial type-three secretion system.