Professor Xi Chen
Department of Civil Engineering and Engineering Mechanics
Columbia University
New York, NY

Monday, August 27, 2007
3:00 pm (CT)
3269 Beckman Institute

Abstract

The gating pathways of mechanosensitive channels of large conductance (MscL) are studied using a molecular dynamics-decorated finite element method (MDeFEM). The phenomenological model treats transmembrane helices as elastic rods and the lipid membrane as an elastic sheet of finite thickness. The interactions between various continuum components are derived from atomistic energy calculations. Upon equi-biaxial tension, the structural variations along the gating pathway are consistent with previous analyses based on structural models and biased molecular-dynamics simulations. Detailed conformational changes and gating mechanisms of MscL when the membrane is under uniaxial/plane strain tension, bending, and torsion are also studied, as well as the interaction among neighboring proteins. In addition, the simulations of patch clamp and nanoindentation experiments are carried out. The MDeFEM framework offers a unique alternative to bridge detailed intermolecular interactions and biological processes occurring at large spatial and timescales. It is envisioned that such a hierarchical multiscale framework will find great value in the study of a variety of biological processes involving complex mechanical deformations such as muscle contraction and mechanotransduction.