Stability of Proteins- Bonds involved

Protein Structure : Bonds involved

•  Primary structure is stabilised by peptide bond.

• Secondary structure; α and β helices are stabilised by H bond.

• Tertiary structure is stabilised by di sulphide bond which is a covalent bond.

• 3D confirmation of protein is maintained by non covalent interactions like electrostatic forces, hydrogen bonds, hydrophobic forces) and covalent interactions (di-sulphide bonds) apart from the peptide bond between individual amino acids.

• Hydrophobic forces or bonding is the major non covalent interaction that determines protein structure, folding and stability.

• Di-sulphide bond between cys residues is the major covalent interaction that stabilizes the 3D native protein.

• Di-sulphide bonds are formed only in oxidising environment of ER and that is why secretory and membrane proteins have extensive di-sulphide bonds.