title: Chemophoresis as a driving force for intracellular organization: Theory and application to plasmid partitioning.
abstract: Biological units such as macromolecules, organelles, and cells are directed to a proper location by gradients of chemicals. We consider a macroscopic element with surface binding sites where chemical adsorption reactions can occur and show that a thermodynamic force generated by chemical gradients acts on the element. By assuming local equilibrium and adopting the grand potential used in thermodynamics, we derive a formula for the "chemophoresis" force, which depends on chemical potential gradients and the Langmuir isotherm. The conditions under which the formula is applicable are shown to occur in intracellular reactions. Further, the role of the chemophoresis in the partitioning of bacterial chromosomal loci/plasmids during cell division is discussed. By performing numerical simulations, we demonstrate that the chemophoresis force can contribute to the regular positioning of plasmids observed in experiments.
authors.affiliation: Cell Architecture Laboratory, Center for Frontier Research, National Institute of Genetics, 1111, Yata, Mishima, Shizuoka 411-8540, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Sugawara
authors.affiliation: Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1, Komaba, Meguro, Tokyo 153-8902, Japan; Complex Systems Biology Project, ERATO, JST, Komaba, Meguro, Tokyo 153-8902, Japan.
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Kaneko
keywords: chemical adsorption; chemical gradient; plasmid partitioning; thermodynamic force