The α-helix and the β-pleated sheet are part of the secondary structure of a protein.
Explanation
- The secondary structure of proteins is formed by local folding patterns of the polypeptide chain, stabilized primarily by hydrogen bonds.
- The α-helix is a coiled structure stabilized by hydrogen bonds between every fourth amino acid within the same chain.
- The β-pleated sheet consists of polypeptide chains aligned side-by-side, held together by hydrogen bonds between strands, forming a sheet-like arrangement.
- These structures contribute to the protein's overall 3D shape but do not involve the side chains (R groups) directly; instead, the bonding occurs along the protein backbone.
Thus, both α-helices and β-pleated sheets are key elements of protein secondary structure.
