A novel method for thermodynamic study on binding of copper ion with Alzheimer’s amyliod β peptide

The interaction of Cu²⁺ with the first 16 residues of the Alzheimer's amyliod β peptide, Aβ (1-16), was studied by employing isothermal titration calorimetry at pH 7.2 and 37℃ in aqueous solution. The Gholamreza Rezaei Behbehani (GRB) solvation model was used to reproduce the enthalpies of Cu²⁺+ Aβ(1-16) interaction over the whole Cu²⁺ concentrations. The binding parameters recovered from the solvation model were attributed to the structural change of Aβ (1-16) due to the metal ion interaction. It was found that there is a set of two identical and non interacting binding sites for Cu²⁺ ions. The molar enthalpy of binding is ΔH=27.895 kJ/mol. The association binding constants are 1.895 μm^-1 and 1.891 μm^-1 for the first and second binding sites respectively.