Macromolecular crowding directs the motion of small molecules inside cells.

ABSTRACT: It is now well established that cell interiors are significantly crowded by macromolecules, which impede diffusion and enhance binding rates. However, it is not fully appreciated that levels of crowding are heterogeneous, and can vary substantially between subcellular regions. In this article, starting from a microscopic model, we derive coupled nonlinear partial differential equations for the concentrations of two populations of large and small spherical particles with steric volume exclusion. By performing an expansion in the ratio of the particle sizes, we find that the diffusion of a small particle in the presence of large particles obeys an advection-diffusion equation, with a reduced diffusion coefficient and a velocity directed towards less crowded regions. The interplay between adv

SUBMITTER: Smith S 

PROVIDER: S-EPMC5493789 | biostudies-literature | 2017 Jun

REPOSITORIES: biostudies-literature