Molecular Mechanisms Underlying the Effects of Urea and the Structural Dynamics of Bovine Serum Albumin

Abstract: The disruption of protein structures by denaturants like urea is well studied, though its molecular mechanisms remain unclear. Using Molecular Dynamics (MD) simulations, we investigated how urea affects the structural stability of Bovine Serum Albumin (BSA) at concentrations from 0 M to 5 M. Our results reveal that urea induces a dehydration/rehydration cycle, characterized by displacement and partial replacement of water molecules in BSAs hydration shell. At low concentrations, urea reduces protein/water hydrogen bonds while enhancing protein-urea interactions. At higher concentrations, urea aggregation limits these interactions, promoting rehydration and changes in tertiary structure, while secondary structure remains largely intact. These findings provide insights into the mechanisms of protein denaturation and stability by urea.