Molecular Motors Interacting with Their Own Tracks

TL;DR

This paper presents a theoretical analysis of molecular motors interacting with their tracks through reversible bond destruction, revealing mechanisms for directed motion, fluctuation suppression, and dynamic transitions in transport behavior.

Contribution

It introduces exactly solvable burnt-bridge models to analyze how reversible and irreversible track modifications influence molecular motor dynamics.

Findings

Reversible bond destruction leads to directed motion and fluctuation reduction.

Dynamic transitions occur at low concentrations of weak links.

Complex behaviors emerge from the interplay of opposing mechanisms.

Abstract

Dynamics of molecular motors that move along linear lattices and interact with them via reversible destruction of specific lattice bonds is investigated theoretically by analyzing exactly solvable discrete-state ``burnt-bridge'' models. Molecular motors are viewed as diffusing particles that can asymmetrically break or rebuild periodically distributed weak links when passing over them. Our explicit calculations of dynamic properties show that coupling the transport of the unbiased molecular motor with the bridge-burning mechanism leads to a directed motion that lowers fluctuations and produces a dynamic transition in the limit of low concentration of weak links. Interaction between the backward biased molecular motor and the bridge-burning mechanism yields a complex dynamic behavior. For the reversible dissociation the backward motion of the molecular motor is slowed down. There is a change in the direction of the molecular motor's motion for some range of parameters. The molecular motor also experiences non-monotonic fluctuations due to the action of two opposing mechanisms: the reduced activity after the burned sites and locking of large fluctuations. Large spatial fluctuations are observed when two mechanisms are comparable. The properties of the molecular motor are different for the irreversible burning of bridges where the velocity and fluctuations are suppressed for some concentration range, and the dynamic transition is also observed. Dynamics of the system is discussed in terms of the effective driving forces and transitions between different diffusional regimes.