Spectroscopic Probe Analysis of Protein-Surfactant Interactions: The BSNSDS System

The interactions and structure of complexes formed between bovine serum albumin (BSA) and the anionic surfactant sodium dodecyl sulfate has been investigated by spectroscopic probe techniques. Steady state and time-resolved fluorescence, electron spin resonance, and deuterium NMR spectroscopy have been employed as a multitechnique approach to investigate the structures which occur along the proteinsurfactant isotherm. Three models of the protein-surfactant complex are considered. The results of the multitechnique approach are consistent with a structure which is predominantly of the "necklace and bead" type in which the unfolded protein wraps around surfactant micelles.