ROLE OF THE KINETIC RELATION IN A PHASE TRANSITION-BASED MODEL FOR MECHANICAL UNFOLDING IN MACROMOLECULES

摘要

We present applications of a model developed to describe unfolding in macromolecules under an axial force. We show how different experimentally observed force-extension behav iors can be reproduced within a common theoretical frame work. We propose that the unfolding occurs via the motion of a folded/unfolded interface along the length of the molecule. The molecules are modeled as one- dimensional continua capable of existing in two metastable states under an applied tension. The interface separates these two metastable states and represents a jump in stretch, which is related to applied force by the worm-like-chain relation. The mechanics of the interface are governed by the Abeyaratne-Knowles theory of phase transitions. The ther-modynamic driving force controls the motion of the interface via an equation called the kinetic relation. By choosing an appropri ate kinetic relation for the unfolding conditions and the macro-molecule under consideration, we have been able to generate a variety of unfolding processes in macromolecules.