Final answer:
Hydrogen bonding is the interaction that stabilizes the α-helix and β-pleated sheet structures in proteins, facilitating the secondary structure critical for protein stability and function.
Step-by-step explanation:
The type of interaction that stabilizes the α-helix and the β-pleated sheet structures of proteins is hydrogen bonding. In an α-helix, hydrogen bonds form between every fourth amino acid, contributing to the helical twist of the amino acid chain
In the β-pleated sheet, hydrogen bonds occur between atoms on the backbone of the polypeptide chain, making the pleats. The R-groups extend above and below these folds. The helical and pleated structures aid in the establishment of the protein's secondary structure, which is crucial for its overall stability and function.