A study on the binding interaction between the imidazole derivative and bovine serum albumin by fluorescence spectroscopy

• Published in: Journal of luminescence 2012-03, Vol.132 (3), p.707-712
• Main Authors: Jayabharathi, Jayaraman, Thanikachalam, Venugopal, Venkatesh Perumal, Marimuthu
• Format: Article
• Language: English
• Subjects: Binding energy; Binding studies; Biological and medical sciences; Bovine serum albumin; Constants; Derivatives; Fluorescence; Fluorescence quenching; Fretting; Fundamental and applied biological sciences. Psychology; Imidazole; Imidazole derivative; Interactions. Associations; Intermolecular phenomena; Molecular biophysics; Serum albumin; Spectroscopy; Synchronous fluorescence spectra
• ISSN: 0022-2313; 1872-7883
• DOI: 10.1016/j.jlumin.2011.10.023

The interaction between the imidazole derivative 2-(2,4-difluorophenyl)-1-phenyl-1H-imidazo[4,5-f][1,10]phenanthroline (dfppip) and bovine serum albumin (BSA) was investigated by fluorescence and UV–vis absorbance spectroscopy. From the experimental results, it was found that the imidazole derivative has strong ability to quench the intrinsic fluorescence of BSA by forming complexes. Electrostatic interactions play an important role to stabilize the complex. The binding constants and the number of binding sites have been determined in detail. The distance (r) between the donor and the acceptor was obtained according to fluorescence resonance energy transfer (FRET). Conformational changes of BSA were observed from synchronous fluorescence spectroscopy. The effect of metal ions such as Cu 2+, Zn 2+, Ca 2+, Mg 2+, Ni 2+, Co 2+ and Fe 2+ on the binding constants between the imidazole derivative and BSA were also studied. ► Interactions between dfppip and BSA were investigated by fluorescence quenching. ► Quenching mechanism mainly arise from the formation of BSA-imidazole complex. ► D→A distance is