Exact Analysis of Ligand-Induced Dimerization of Monomeric Receptors

Abstract

This paper analyzes the equilibria involved in the dimerization of monomeric receptors with homo-bifunctional ligands. We provide analytical expressions that can be used to estimate the concentration of each species present in a mixture of homo-bifunctional ligand and monomeric proteins, given initial conditions defining the total concentration of bivalent ligand [L₂]₀, the total concentration of protein [P]₀, one dissociation constant K_d, and a parameter to account for cooperativity α. We demonstrate that the fraction of protein present in a complex of two proteins and one bivalent ligand (P·L₂·P) is maximized at [L₂]₀ = K_d/2 + [P]₀/2.