# Exclusion process subject to conformational size changes

## TL;DR

This paper models stochastic transport of particles with conformational size changes on a one-dimensional substrate, extending the exclusion process to include contraction and expansion steps, with implications for molecular motors and ribosomes.

## Contribution

It introduces a novel exclusion process model incorporating conformational size changes and provides analytical predictions validated by simulations.

## Key findings

- Current-density relation can be significantly affected by size changes
- Model predictions align well with simulation results across regimes
- Symmetries in the model are identified and utilized

## Abstract

We introduce a model for stochastic transport on a one-dimensional substrate with particles assuming different conformations during their stepping cycles. These conformations correspond to different footprints on the substrate: in order to advance, particles are subject to successive contraction and expansion steps with different characteristic rates. We thus extend the paradigmatic exclusion process, provide predictions for all regimes of these rates that are in excellent agreement with simulations, and show that the current-density relation may be affected considerably. Symmetries are discussed, and exploited. We discuss our results in the context of molecular motors, confronting a hand-over-hand and an inchworm stepping mechanism, as well as for ribosomes.