Structural Studies of Protein-Surfactant Complexes


The structure of protein-surfactant complexes of two proteins bovine serum albumin (BSA) and lysozyme in
presence of anionic surfactant sodiumdodecyl sulfate (SDS) has been studied using small-angle neutron scattering
(SANS). It is observed that these two proteins form different complex structures with the surfactant. While BSA protein
undergoes unfolding on addition of surfactant, lysozyme does not show any unfolding even up to very high surfactant
concentrations. The unfolding of BSA protein is caused by micelle-like aggregation of surfactant molecules in the
complex. On the other hand, for lysozyme protein there is only binding of individual surfactant molecules to protein.
Lysozyme in presence of higher surfactant concentrations has protein-surfactant complex structure coexisting with pure
surfactant micelles.
Keywords: Small-angle neutron scattering, Protein-surfactant complex, Protein unfolding. S. N. Chodankar, V. K. Aswal and A. G. Wagh
Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai-400 085, India