What changes occur during denaturation of proteins, and how does it affect their secondary and tertiary structures?

During protein denaturation, external factors like heat or pH disrupt non-covalent interactions stabilizing the native structure. The process leads to the unraveling of secondary structures (α-helices, β-sheets) and the distortion or loss of tertiary structure. Hydrogen bonds, van der Waals forces, and hydrophobic interactions, crucial for maintaining these structures, are disrupted. However, the primary structure (amino acid sequence) usually remains intact. Denaturation renders proteins inactive, as their functional three-dimensional shape is compromised. While some proteins can refold upon removal of denaturing agents, irreversible denaturation may result in permanent loss of structure and function.