Final answer:
The α-helix is the secondary structure stabilized by hydrogen bonds between the carbonyl oxygen and N-H hydrogen of amino acids four residues apart.
Step-by-step explanation:
The secondary structure referred to in the question is the α-helix. This structure is one of the two most common secondary structures found in proteins, alongside the β-pleated sheet. The α-helix is a coiled structure, where hydrogen bonds stabilize the helix.
These bonds form between the carbonyl (C=O) oxygen atom of one amino acid and the N-H hydrogen atom of the amino acid positioned four residues ahead on the primary amino acid chain.
This specific interaction contributes to the overall stability and shape of the protein, which is critical for its function.
In addition to the α-helix, the β-pleated sheet is another secondary structure that is stabilized by hydrogen bonds, but in this case, the bonding occurs between segments of the peptide chain lying side by side.
Both the α-helix and β-pleated sheet are essential elements of a protein's secondary structure, determining how the chain of amino acids folds in space and hence influencing the protein's overall three-dimensional conformation.