What is the shape of an α-helix structure?

The α-helix is a common structural motif in proteins characterized by its coiled, spiral-like shape. This helical configuration is stabilized by hydrogen bonds between the backbone amide and carbonyl groups of the amino acids, specifically between the N-H group of one amino acid and the C=O group of another located four residues earlier in the sequence.

This arrangement not only provides stability to the protein structure but also contributes to the overall three-dimensional conformation of the protein. The right-hand coil of the helix allows for efficient packing of the protein structure and plays a significant role in the functionality of many proteins. In contrast to the other structures mentioned, such as flat sheets, random coils, or rigid layers without bonding, the unique spiral structure of the α-helix is essential for its role in the biological functions and interactions of proteins.