Spatio-temporal evolution model for competitive ligand binding

C.A. CONDAT; P.P. DELSANTO; D. IORDACHE; G. PEREGO; E. RUFFINO

Materials Science of the Cell

Materials Research Society

Año: 1998; p. 193 - 198

Ligand binding is an essential step in many biological and biochemical processes, notably protein activation. In many cases, the binding rates are determined by competition: blockers competing with ligands or decoys competing with receptors. Often, the diffusivities of the various species also play a key role. The usual modeling of these processes, however, either involves well-mixed systems, for which spatial variations are neglected, or steady-state situations for which all evolution has ceased. The model presented here can instead account for the spatial variations that originate as a consequence of inhomogeneous initial conditions and localized binding sites. It describes their evolution in time due to a combination of mechanisms of diffusion, competition and reaction. The model, which is formulated in terms of a coupled system of equations for the probability densities of the various populations, is easy to adapt to different specific conditions and is particularly well suited for numerical calculations, e.g., on a parallel computer. Since it yields concrete predictions, it can be readily used to predict the concentrations and distributions of the various species that are needed to obtain prescribed responses.