Reduction of self-diffusion coefficient in a coarse-grained model of cytoplasm

Abstract

Theoretical predictions for polydisperse hard-sphere suspensions with and without hydrodynamic interaction are applied to a coarse-grained model of bacterial cytoplasm, which consists of 15 species of spherical particles. Short-time and long-time self-diffusion coefficients of each species are obtained to the first order in concentration. It is shown that the hydrodynamic interaction leads to a large reduction of diffusivity for small particles such as green fluorescent proteins. Moreover, a heuristic modification of the above theory to make it valid at higher concentrations is presented.