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°C 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. Supported by the University of Imam Khomeini (Qazvin) and University of Tehran and Iranian National Science Foundation (INSF)