How do hydrogen bonds help proteins keep their shapes?

Hydrogen bonds are essential for maintaining the structural integrity and functional shape of proteins. Because proteins are polypeptides composed of amino acids, they contain repeating peptide links (—CO—NH—) that provide both the donor (NH) and acceptor (oxygen) sites necessary for hydrogen bonding.1

These interactions help determine protein shape in two primary ways:

• Secondary Structure: Hydrogen bonding between peptide groups allows the polypeptide chain to fold into specific, stable configurations, most notably the $\alpha$ helix or the $\beta$-pleated sheet.1
• Tertiary Structure: Beyond the backbone, hydrogen bonds form between the side chains of amino acids, contributing to the complex three-dimensional folding of the protein.2

Although individual hydrogen bonds are weaker than covalent bonds, the large number of these interactions within a single protein molecule provides the stability required for the protein to achieve its functional configuration. This precise shape is critical, as it dictates how an enzyme interacts with other molecules to perform its biological role.231