Zahra Aramesh-Boroujeni - Young Researchers and Elite Club, Najafabad Branch, Islamic Azad University, Najafabad, Iran
Meissam Noroozifar - Department of Chemistry, University of Sistan & Baluchestan, Zahedan, Iran

In this work, binding behavior of the terbium(III) and holmuim(III) complexes containing 1,10-phenanthroline (phen) ligand with human serum albumin (HSA) were studied by UV-vis, fluorescence and molecular docking examinations. The experimental data indicated that these lanthanide complexes have high binding affinity with HSA by effectively quenched the fluorescence of HSA via static mechanism. The binding parameters, the type of interaction, the value of resonance energy transfer and the binding distance between complexes and HSA were estimated from the analysis of fluorescence measurements and Förster theory. The thermodynamic parameters suggested that van der Waals interactions and hydrogen bonds play an important role in the binding mechanism. The results of molecular docking calculations assessed the microenvironment residues around the bound mentioned complexes and represent site 3 of HSA, located in subdomain IB, as the most probable binding site for these ligands. The computational results kept in good agreement with experimental data.

Lanthanide complex, Human serum albumin, Binding interaction, Molecular docking