Binding of ciprofloxacin to bovine serum albumin: Photophysical and thermodynamic aspects.

Bijan K Paul, Nikhil Guchhait, Subhash Chandra Bhattacharya

Journal of photochemistry and photobiology. B, Biology 2017 Jul

filter terms:

The present work reveals the study of interaction of a promising chemotherapeutic drug ciprofloxacin (CFX) with a model transport protein bovine serum albumin (BSA). The occurrence of the drug-protein interaction is found to result in significant modulations of the fluorescence excitation and emission spectroscopic properties of CFX following interaction with BSA. However, the major focus of the study underlies a critical insight into the quantitation of the drug-protein interaction phenomenon. To this end, we have exploited the isothermal titration calorimetric (ITC) technique to quantify the affinity constant (Ka) and stoichiometry (n) of the CFX-BSA interaction with simultaneous revelation of the accompanying thermodynamics of the interaction process. In this context, our discussion also sheds light on the lacuna surrounding various experimental methodologies for evaluation of drug-protein binding parameters. Our endeavor also extends to elucidation of the kinetic parameters and energy of activation (Ea) of the CFX-BSA interaction. The present study also delineates the modulation of the dynamical aspects of CFX following interaction with BSA. The rotational relaxation dynamics of the protein-bound drug reveals the not-so-common "dip-rise-dip" anisotropy decay. Furthermore, the effect of drug binding on the native protein conformation has been evaluated from circular dichroism (CD) spectroscopy which reveals partial rupture of the protein secondary structure. Copyright © 2017 Elsevier B.V. All rights reserved.

Citation

Bijan K Paul, Nikhil Guchhait, Subhash Chandra Bhattacharya. Binding of ciprofloxacin to bovine serum albumin: Photophysical and thermodynamic aspects. Journal of photochemistry and photobiology. B, Biology. 2017 Jul;172:11-19