An escape rate analysis for pulling experiments based on energy landscapes in two reaction coordinates

The structural dynamics of biopolymers such as proteins are described in the context of their conformational energy landscapes. In optical-tweezer pulling experiments, features of the energy landscapes are extracted from the observed distribution of the critical force at which the polymer unfolds, and typically the analysis is based on a one-dimensional (1D) reaction coordinate, the extension. But a 1D analysis is inadequate when various possible folded configurations are degenerate in the end-to-end length. We present an analytical framework for the well escape rate in the context of an effective 2D landscape. We test our analysis against simulated pulling experiments and verify our ability to extract meaningful well parameters.