What provides stability in the structure of α-keratin?

The stability of α-keratin, a type of fibrous protein commonly found in hair, nails, and the outer layer of skin, primarily relies on disulfide bonds that form between cysteine side chains of the polypeptide chains. These covalent bonds create cross-links between different helices, which significantly enhance the structural integrity and resilience of the protein.

Disulfide bonds are particularly important in keratin because they provide robustness against mechanical stress and environmental factors. Keratin’s strength and rigidity are largely attributed to the extensive network of these disulfide bridges, which reinforces the overall three-dimensional structure of the protein.

Although peptide bonds are essential for forming the primary structure and hydrogen bonds contribute to the stabilization of the individual helices, it is the disulfide bonds that play a critical role in holding together multiple helices, resulting in the unique properties of α-keratin. Therefore, when considering the major contributors to the structural stability of α-keratin, the disulfide bonds are the key players.