Traffic of interacting ribosomes: effects of single-machine mechano-chemistry on protein synthesis

Abstract

Many ribosomes simultaneously move on the same messenger RNA (mRNA), each separately synthesizing the protein coded by the mRNA. Earlier models of ribosome traffic represent each ribosome by a ``self-propelled particle'' and capture the dynamics by an extension of the totally asymmetric simple exclusion process (TASEP). In contrast, here we develope a theoretical model that not only incorporates the mutual exclusions of the interacting ribosomes, but also describes explicitly the mechano-chemistry of each of these individual cyclic machines during protein synthesis. Using analytical and numerical techniques of non-equilibrium statistical mechanics, we analyze this model and illustrate its power by making experimentally testable predictions on the rate of protein synthesis in real time and the density profile of the ribosomes on some mRNAs in E-Coli.