Statistical thermodynamics of the stability of multivalent ligand-receptor complexes.

Multivalent ligands can form ligand-receptor complexes that are orders of magnitude more stable than their monovalent counterparts. A theory of this "enhancement effect" based on fundamental principles of statistical thermodynamics is presented. A key finding is a simple analytical expression that provides clear and direct insight into the mechanism by which the enhanced stability of the multivalent ligand-receptor complex can be achieved. The theory explains experimental data on the activation of ion channels in the membranes of cells by polymer-linked divalent ligands.