Association kinetics with coupled diffusion. An extension to coiled-chain macromolecules applied to the lac repressor-operator system.

The association of a molecule onto a specified binding site on a large chain-like macromolecule is described in the "sliding" model, where the molecule is allowed to move along the chain in a one-dimensional diffusion which is coupled to the three-dimensional diffusion in solution. The present work extends a previous one by treating the chains more generally as coiled instead of straight. The model is applied to the lac repressor-operator association. A general expression for the rate of unspecific attachment to a chain-like macromolecule is also derived.