Enthalpy-entropy compensation and cooperativity as thermodynamic epiphenomena of structural flexibility in ligand-receptor interactions.

ABSTRACT: Ligand binding is a thermodynamically cooperative process in many biochemical systems characterized by the conformational flexibility of the reactants. However, the contribution of conformational entropy to cooperativity of ligation needs to be elucidated. Here, we perform kinetic and thermodynamic analyses on a panel of cycle-mutated peptides, derived from influenza H3 HA(306-319), interacting with wild type and a mutant HLA-DR. We observe that, within a certain range of peptide affinity, this system shows isothermal entropy-enthalpy compensation (iEEC). The incremental increases in conformational entropy measured as disruptive mutations are added in the ligand or receptor are more than sufficient in magnitude to account for the experimentally observed lack of free-energy decrease coopera

SUBMITTER: Ferrante A 

PROVIDER: S-EPMC3349339 | biostudies-literature | 2012 Apr

REPOSITORIES: biostudies-literature