Interactions between bovine serum albumin and gemini surfactant alkanediyl-α, ω-bis(dimethyldodecyl-ammonium bromide)

Abstract

Interactions between bovine serum albumin (BSA) and cationic gemini surfactant alkanediyl-α,ω-bis(dimethyldodecyl-ammonium bromide) (12-n-12, n = 3, 4, 6) in aqueous solution have been investigated by measuring fluorescence, UV-vis transmittance, dynamic lighting scattering, and circular dichroism. Compared to a traditional surfactant dodecyltrimethylammonium bromide (DTAB), 12-n-12 interacts with BSA more strongly. With increasing concentration, 12-n-12 first binds specifically onto BSA leading to the unfolding and aggregation of BSA, and the decrease in α-helix content; and then forms micelle-like complexes along the unfolded BSA chains. A gemini surfactant with a longer spacer has a larger effect on BSA unfolding due to a stronger hydrophobic interaction. © 2006 Wiley Periodicals, Inc.