Force-dependent unbinding rate of molecular motors from stationary optical trap data

TL;DR

This paper introduces two methods to determine the force-dependent unbinding rate of molecular motors from stationary optical trap data, validated with simulations and applied to kinesin-1.

Contribution

It presents novel analytical and statistical approaches for extracting unbinding rates from experimental data, enhancing understanding of motor-filament interactions.

Findings

Methods accurately recover unbinding rates from simulated data.

Application to kinesin-1 data demonstrates practical utility.

Analytical models fit experimental force distributions effectively.

Abstract

Molecular motors walk along filaments until they detach stochastically with a force-dependent unbinding rate. Here, we show that this unbinding rate can be obtained from the analysis of experimental data of molecular motors moving in stationary optical traps. Two complementary methods are presented, based on the analysis of the distribution for the unbinding forces and of the motor's force traces. In the first method, analytically derived force distributions for slip bonds, slip-ideal bonds, and catch bonds are used to fit the cumulative distributions of the unbinding forces. The second method is based on the statistical analysis of the observed force traces. We validate both methods with stochastic simulations and apply them to experimental data for kinesin-1.