The effect of local dissociation on dynamics of interacting molecular motors

Abstract

Successful functioning of all living systems depends on several classes of active enzymatic molecules known as biological molecular motors. They are involved in processes that require the application of mechanical forces such as cellular transport, muscle functioning, synthesis of proteins and nucleic acids and many others. Experimental studies suggest that most biological molecular motors function collectively by interacting with each other and moving along linear tracks, from which they occasionally dissociate at specific locations. We develop a theoretical model to investigate the multi-particle dynamics of interacting molecular motors with local dissociations. It is specifically stimulated by ribosomes motion along ribonucleic acid (RNA) molecules during the protein synthesis when the ribosome complex might dissociate into the solution by encountering a specially localized region on RNA. In our theoretical approach, we model the dynamics of molecular motors as onedimensional totally asymmetric simple exclusion processes for interacting particles. Using a cluster mean-field approach, which partially takes into account the correlations in the system, stationary properties such as particle currents, densities and phase diagrams are explicitly calculated. It is found that the presence of local dissociations increases the number of possible stationary phases. Furthermore, the strength of interactions between molecular motors, the modification of transition rates due to interactions and the frequency of dissociations strongly influence the dynamics of molecular motors. The microscopic origin of these observations are discussed. Our theoretical predictions are fully supported by Monte Carlo computer simulations.