Evaluation of DNA, BSA binding, DNA cleavage and antimicrobial activity of ytterbium(III) complex containing 2,2'-bipyridine ligand

Abstract

In order to estimate the biological potential of a synthesized complex [Yb(bpy)₂Cl₃.OH₂] where bpy is 2,2'-bipyridine, its binding behavior with fish salmon-DNA (FS-DNA) and bovine serum albumin (BSA) were studied by different kinds of spectroscopy and molecular modeling methods. This complex was selected for its antibacterial and antifungal activities as well as the DNA cleavage activities were examined by agarose gel electrophoresis. The analyses of fluorescence data at four temperatures were done in order to evaluate the binding and thermodynamic parameters of the interaction of Yb(III) complex with DNA and BSA. The experimental results indicated that the major binding modes were based on groove binding with DNA and BSA. In addition, iodide quenching studies, ethidium bromide (EtBr) exclusion assay, ionic strength effect, circular dichroism, and viscosity studies reflected the binding of Yb(III) complex explicitly with the FS-DNA mainly in a groove binding mode. Moreover, molecular docking studies indicated that this complex was bound to the minor groove of DNA and to polar and apolar residues located in the subdomain IB of BSA (site 3). Also, the results of competitive experiments assessed site 3 of BSA as the most probable binding site for this complex. The molecular docking results were in good agreement with our experimental results. From both experimental and docking results, the binding constant values displayed the remarkably high affinity of Yb(III) complex to DNA as well as BSA.

Communicated by Ramaswamy H. Sarma

Keywords:

• Antibacterial activity
• binding interaction
• bovine serum albumin
• fish salmon-DNA
• molecular docking
• ytterbium(III) complex

Additional information

Funding

The financial supports of Research Councils of University of Sistan and Baluchestan, Isfahan University of Medical Sciences and Isfahan University are gratefully acknowledged. K. K. acknowledges financial support from the Canada Research Chair Tier-2 award for “Bioelectrochemistry of Proteins” (Project No. 950-231116), Ontario Ministry of Research and Innovation (Project No. 35272), Discovery Grant (Project No. 3655) from Natural Sciences and Engineering Research Council of Canada (NSERC), and Canada Foundation for Innovation (Project No. 35272).