Abstract
Cromolyn sodium (CS), an anti-inflammatory drug is used in the treatment of allergic disorders. Bovine serum albumin (BSA) a blood plasma protein is used as a model protein for studying protein folding and ligand binding mechanism as it is the main transporter protein which decides the disposition and pharmacodynamics of numerous drugs. In this study, interaction of CS with BSA was investigated using isothermal titration calorimetry, UV-vis, fluorescence, circular dichroism (CD) spectroscopy and molecular docking techniques. Steady state fluorescence data revealed that BSA-CS complex formation occurred through static mode of quenching. Negative values of Gibbs free energy change and enthalpy change showed that BSA-CS complexation was spontaneously favorable and enthalpy driven. CS preferentially interacted at Sudlow’s site I (sub-domain IIA) of BSA and the finding was further substantiated by molecular docking study. The binding of CS induced changes in secondary motif of BSA resulting decrease of α-helical content as evident from CD. We explored detailed thermodynamic and structural parameters of interaction of CS to BSA that will be helpful for understanding the more precise binding mechanism of the drug at molecular level.
Communicated by Ramaswamy H. Sarma
Acknowledgments
The authors are acknowledged to Chairman, Department of Chemistry, AMU, Aligarh for providing the necessary facilities for the completion of this work. One of the authors (S.K.) gratefully acknowledged to UGC, New Delhi for awarding Maulana Azad National Fellowship (MANF).
Disclosure statement
No potential conflict of interest was reported by the authors.
Funding
Financial supports from UGC (SAP-DRS-II) and DST (FIST and PURSE) schemes are gratefully acknowledged.