In the process of translation, a protein is synthesized based on m-DNA. After protein synthesis, posttranslational modifications (covalent chemical and enzymatic modification of the protein, protein splicing, protein folding) begin during which they acquire their final structure.
Peptide bond - forms amino acid compounds in the polypeptide chain (primary protein structure).
The secondary structure (α-helix, β-structure) is formed with the participation of hydrogen bonds.
The tertiary structure is composed of secondary structure elements stabilized by weak non-covalent interactions between functional groups of amino acid radicals (disulfide bonds, hydrogen bonds, ionic bonds, hydrophobic interactions).
Interaction of polypeptide chains in the formation of the quaternary structure is due to the formation of hydrogen and ionic bonds, as well as hydrophobic interactions.
The hemoglobin molecule consists of polypeptide chains (primary structure) twisted in a spiral (secondary structure), which, in turn, are rolled up in a ball (tertiary structure) and combined into four (quaternary structure).