Understanding the catch-bond kinetics of biomolecules on a one-dimensional energy landscape

In spite of extensive investigations, the force-dependent unfolding/rupturing rate k(F) of biomolecules still remains poorly understood. A famous example is the frequently observed switch from catch-bond behaviour, where force anti-intuitively decreases k(F), to slip-bond behaviour where increasing force accelerates k(F). A common consensus in the field is that the catch-to-slip switch behaviour cannot be explained in a one-dimensional energy landscape, while this view is mainly built upon assuming that force monotonically affects k(F) along each available transition pathway. In this work, by applying Kramers kinetic rate theory to a model system where the transition starts from a single native state through a pathway involving sequential peeling of a polymer strand until reaching the transition state, we show the catch-to-slip switch behaviour can be understood in a one-dimensional energy landscape by considering the structural-elastic properties of molecules during transition. Thus, this work deepens our understanding of the force-dependent unfolding/rupturing kinetics of molecules/molecular complexes