A systematic study of bovine serum albumin (BSA) and sodium dodecyl sulfate (SDS) interactions by surface tension and small angle X-ray scattering.

Article Details

Citation

Copy to clipboard

Santos SF, Zanette D, Fischer H, Itri R

A systematic study of bovine serum albumin (BSA) and sodium dodecyl sulfate (SDS) interactions by surface tension and small angle X-ray scattering.

J Colloid Interface Sci. 2003 Jun 15;262(2):400-8.

PubMed ID

16256620 [ View in PubMed

]

Abstract

Classical parameters obtained from surface tension technique coupled to small angle X-ray scattering (SAXS) measurements gave support to investigate conformational changes in the bovine serum albumin (BSA)-sodium dodecyl sulfate (SDS) complexes, as well as the size of the micelle-like clusters distributed along the polypeptide chain. The studied systems were composed of 1 wt% of BSA in the absence and presence of increasing SDS molar concentration up to 80 mM, under experimental conditions of low ionic strength and pH 5.40. At SDS concentrations below the critical aggregation concentration (cac) of 2.2 mM, SAXS results indicate that the detergent does not modify the native protein conformation. However, the beginning of protein unfolding, evidenced by SAXS through an increase in the values of radius of gyration Rg and protein maximum dimension Dmax, is coincident with the onset of SDS cooperative binding to BSA identified by the first breakpoint in the surface tension-SDS profile. Further SDS addition leads to the formation of micelle-like aggregates randomly distributed along the unfolded polypeptide chain, consistent to a necklace and bead model. The SAXS data also demonstrate that the SDS micelles grow in size up to 50 mM detergent. At 50 mM surfactant, the micelles stop growing. This concentration is near the BSA saturation binding by SDS measured by dialyzes and indicated by the second breakpoint in surface tension-SDS profile. The SAXS and surface tension data are also consistent with the formation of free micelles in equilibrium with BSA-SDS complexes for surfactant amount above the saturation.

DrugBank Data that Cites this Article

Drug Carriers

Drug	Carrier	Kind	Organism	Pharmacological Action	Actions
Sodium lauryl sulfate	Serum albumin	Protein	Humans	Unknown	Binder	Details