Tertiary Structure
The three-dimensional shape of a peptide or protein, determined by interactions between amino acid side chains including hydrogen bonds, ionic bonds, hydrophobic interactions, and disulphide bridges. Tertiary structure is essential for biological function and receptor binding.
Technical Context
Tertiary structure is determined by interactions between amino acid side chains: hydrophobic interactions (non-polar residues cluster in the molecule's interior), hydrogen bonds, ionic bonds (salt bridges between charged residues), van der Waals forces, and disulphide bonds between cysteine residues. For therapeutic peptides, tertiary structure directly affects receptor binding — the peptide must adopt the correct conformation to fit into the receptor binding site. Longer peptides and proteins have more complex tertiary structures. Manufacturing processes must preserve correct tertiary structure; denaturation (unfolding) can result in loss of biological activity and increased immunogenicity.