Secondary structure transitions of Bovine serum albumin induced by temperature variation

Abstract

Secondary structure transitions of Bovine Serum Albumin (BSA) in H2O and D2O under temperature variation were investigated by in-situ IR spectral analysis and they were found to exhibit the same tendency with the only difference that the significant transition temperature of BSA's secondary structure moved towards a lower temperature in D2O. Before this significant transition temperature, the native secondary structures of BSA were essentially changing in a cooperative fashion with temperature variation, except for the intermolecular β-sheet (high-wavenumber) which increased as a result of thermal denaturation at a later stage. After the transition temperature, the relative contents of α-helix and extended chain continued to drop sharply and they were transformed into random coil, β-turn and β-sheet.