Photo-CIDNP Study of the Interaction of Tyrosine with Nifedipine. An Attempt to Model the Binding Between Calcium Receptor and Calcium Antagonist Nifedipine

This article proposes a new approach to the modeling of the molecular-level mechanism of ligand–receptor interaction for Ca2+ receptor binding site. Chemically induced dynamic nuclear polarization (CIDNP) technique has been used to unravel fine details of the reaction in the model system composed of one of the known Ca2+ antagonist drugs, nifedipine (NF), and isolated amino acid residuals (e.g. tyrosine [Tyr]) of Ca2+ receptor binding site. It has been conclusively demonstrated that the reaction between NF and Tyr resulting in the oxidation product—nitroso form of NF—obeys the radical mechanism. CIDNP data in combination with the results of mathematical modeling of the structures of ligand–receptor complexes have allowed to propose the mechanism of the interaction of NF with Ca2+ receptor binding site.