Final answer:
Hydrogen bonding, ionic bonding, and disulfide linkages stabilize the α helix and β pleated sheet structures of proteins.
Step-by-step explanation:
The type of interaction that stabilizes the α helix and the β pleated sheet structures of proteins is hydrogen bonding. Hydrogen bonding forms between highly electronegative oxygen or nitrogen atoms and hydrogen atoms attached to other oxygen or nitrogen atoms. This type of bonding is extremely important in both the intra- and intermolecular interactions of proteins.
Ionic bonding and disulfide linkages also play a role in stabilizing the tertiary structure of proteins. Ionic bonds result from electrostatic attractions between positively and negatively charged side chains of amino acids, while disulfide linkages occur when two cysteine amino acid units are brought close together and the sulfur atoms in their sulfhydryl groups form a covalent bond. Disulfide linkages have a strong stabilizing effect on the tertiary structure.