Molecular interaction of cationic gemini surfactant with bovine serum albumin: A spectroscopic and molecular docking study

Herein, we report the effect of N,N'-bis(dodecyloxycarbonylmethyl)-N,N,N',N'-tetramethy1-1,2-ethanediammonium dibromide (dodecyl betainate gemini or DBG) on the structure and function of bovine serum albumin (BSA) by using fluorescence, time resolved fluorescence, circular dichroism and dynamic light scattering techniques. The Stern-Volmer quenching constants K-sv and the corresponding thermodynamic parameters viz Delta H, Delta G and Delta S have been estimated by the fluorescence quenching method. The results indicated that DBG binds spontaneously with BSA through hydrophobic interaction. Time resolved fluorescence data show that the quenching follows the static mechanism pathway. It can be seen from far-UV CD spectra that the alpha-helical network of BSA is disrupted and its content increases from 71% to 79% at lower concentrations which again decreases to 38% at higher concentration. DLS measurements suggested that hydrodynamic radius (R-h) decreases in the presence of 30 and 40 mu M of DBG while it increases when the concentration of DBG was 70 and 100 mu M. The molecular docking study indicated that DBG is embedded into subdomain IIA of BSA and binds with the R-914, R-195 and R-217 residues by hydrogen bonding and by hydrophobic interaction. (C) 2014 Elsevier Ltd. All rights reserved.