Cooperative crosslink (un)binding in slowly driven bundles of semiflexible filaments

TL;DR

This study combines simulations and theory to explore how the elastic properties of filament bundles and crosslinker mechanics influence cooperative unbinding, revealing a discontinuous binding affinity drop and tunable time-scales.

Contribution

It demonstrates how crosslinker stiffness controls cooperative unbinding and elastic properties in filament bundles through combined simulation and theoretical analysis.

Findings

Discontinuous drop in binding affinity with increased deformation.

Crosslinker stiffness affects elastic properties and unbinding dynamics.

Time-scales can be tuned from binding rate to escape time.

Abstract

Combining simulations and theory I study the interplay between bundle elastic degrees of freedom and crosslink binding propensity. By slowly driving bundles into a deformed configuration, and depending on the mechanical stiffness of the crosslinking agent, the binding affinity is shown to display a sudden and discontinuous drop. This indicates a cooperative unbinding process that involves the crossing of a free-energy barrier. Choosing the proper crosslinker, therefore, not only allows to change the composite elastic properties of the bundle, but also the relevant time-scales, which can be tuned from the single-crosslink binding rate to the much longer escape time over the free-energy barrier.