Correlation of FRET efficiency with conformational changes of proteins in ionic and nonionic surfactant environment

Abstract

We have studied the effect of interaction of surfactants on the FRET process in aqueous solution from transport proteins, BSA and HSA to the probe molecule, sodium salt of anthracene 1,5-disulphonate (1,5-AS). Cationic surfactant CTAB and gemini, anionic surfactant SDS and nonionic surfactant igepal-630 have been used for our investigation as surfactants and micellar solution. In organized media denaturation of protein occurs. Denaturation of protein has also been observed in presence of 1,5-AS. This has been established from steady state, time resolved fluorescence and circular dichroism (CD) studies in homogeneous and heterogeneous environments. Helecity calculations from CD spectra have also supported the results. Nonionic and ionic micellar solutions have been found to directly affect the protein helicity and the FRET parameters. The FRET parameters and denaturation of proteins in homogeneous and heterogeneous media have been compared.