Pathways of mechanical unfolding of FnIII_{10}: low force intermediates

TL;DR

This study uses a simplified model to explore the mechanical unfolding pathways of FnIII_{10} fibronectin domain, revealing two closely spaced intermediates at low forces and confirming experimental results at high forces.

Contribution

It introduces an Ising-like model to analyze low force unfolding intermediates, providing new insights into the stochastic transition pathways of FnIII_{10}.

Findings

Identification of two low-force intermediates with similar elongations.

Confirmation of high-force unfolding pathways consistent with experiments.

Prediction of stochastic transitions between intermediates.

Abstract

We study the mechanical unfolding pathways of the $FnIII_{10}$ domain of fibronectin by means of an Ising--like model, using both constant force and constant velocity protocols. At high forces and high velocities our results are consistent with experiments and previous computational studies. Moreover, the simplicity of the model allows us to probe the biologically relevant low force regime, where we predict the existence of two intermediates with very close elongations. The unfolding pathway is characterized by stochastic transitions between these two intermediates.