Interaction of Irbesartan with Bovine Hemoglobin Using Spectroscopic Techniques and Molecular Docking

The binding of irbesartan to bovine hemoglobin (BHb) has been investigated for the first time by using UV-Vis absorption, fluorescence, circular dichroism (CD), and molecular docking. The binding site number n and binding constant K were calculated to be 1 and 2.41 x 10(5)M(-1), respectively. The alternations of protein secondary structure in the presence of irbesartan was demonstrated using CD spectroscopy. Furthermore, molecular docking indicated that irbesartan could bind to the site 2 of BHb. The analysis of the binding site of irbesartan within the BHb molecule suggested that hydrophobic interaction, hydrogen bond formation, and electrostatic interaction could account for the binding of irbesartan. The hydrogen bond of irbesartan with His87 in the C chain of BHb has been formed. The electrostatic energy, van der Waals energy, and binding free energy were calculated to be -460.3, -224.2, and-684.5 kcal . moL(-1), respectively.