Physicochemical study of biomolecular interactions between lysosomotropic surfactants and bovine serum albumin

Abstract

The interactions between two cationic lysosomotropic surfactants (2-dodecanoyloxyethyl)trimethylammonium bromide (DMM-11) and (2-dodecanoyloxypropyl)trimethylammonium bromide (DMPM-11) with bovine serum albumin (BSA) in Hepes buffer (pH=7.4) were systematically studied by surface tension, fluorescence and circular dichroism (CD) spectroscopy and isothermal titration calorimetry (ITC). Furthermore, the size of the micellar aggregates and the polydispersity indexes of both cationic surfactants were studied by dynamic light scattering technique (DLS). The hydrodynamic radii, micellar volumes and aggregation numbers were calculated using a method based on density functional theory (DFT). The results showed that, in both cases, the surface tension was modified upon addition of BSA, and the critical micelle concentration (CMC) values of DMM-11 and DMPM-11 were higher in the presence of BSA. The fluorescence intensity of BSA decreased significantly as the concentration of both cationic surfactants increased and this effect was attributed to the formation of surfactant-BSA complexes. Synchronous fluorescence spectrometry showed the binding-induced conformational changes in BSA. Finally, CD and DLS results revealed the occurrence of changes in the secondary structure of the protein in the presence of both surfactants. In conclusion, understanding the interactions between lysosomotropic surfactants and BSA is required to explore their potential applications in medicine.

Self-Assembly of the Bio-Surfactant Aescin in Solution: A Small-Angle X-ray Scattering and Fluorescence Study

“…Above cmc aescin,T(WP) a reproducible increase of SFT is visible. A similar behavior was also observed for different surfactants like sodium dodecyl sulfate (SDS) and cationic lysosomotropic substances [53][54][55]. In all cases, the increase in the surface tension above the cmc was assigned to impurities of the surfactants, whereby a substance with a higher surface activity compared to the surfactant investigated might be present [55].…”

Can the Isothermal Calorimetric Curve Shapes Suggest the Structural Changes in Micellar Aggregates?

“…Isothermal Titration Calorimetry (ITC) has recently become a commonly used technique in the studies of intermolecular interactions essential for cellular activity [1][2][3][4][5]. This sensitive analytical method proved especially useful when monitoring aggregation processes in colloidal solutions [6][7][8][9]. Among amphiphilic compounds, surfactants attract widespread attention for their potential applications in industry and medicine [10][11][12].…”

Metal-Biosurfactant Complexes Characterization: Binding, Self-Assembly and Interaction with Bovine Serum Albumin

“…Interactions of proteins with surfactants have been extensively studied for the past few years due to their numerous applications in biological and industrial systems [18,19,20]. Investigating the interaction of biological active compounds with albumins may provide useful information on the structural features of drug-protein complexes that determine the therapeutic effectiveness of drugs [21,22,23].…”

“…Thus, the study of the binding of probes or drugs with albumins becomes a relevant research field in chemistry, life sciences, and clinical medicine [19,25]. Several biophysical methods such as surface tension analysis, fluorescence and circular dichroism (CD) spectroscopy, and molecular docking have been used to unravel the interactions between surfactants and proteins [18,20].…”