What type of bond is directly involved in the formation of an α-helix?a. peptide bonds between amino acid residuesb. hydrogen bonds between amino acid residuesc. van der Waals interactions between nonpolar residuesd. disulfide bonds between cysteine residues

Verified step by step guidance

1. Identify the structure in question: the α-helix is a common secondary structure in proteins.
2. Understand that secondary structures are stabilized by interactions between the backbone atoms of the polypeptide chain.
3. Recall that peptide bonds are covalent bonds that link amino acids together in a chain, forming the primary structure, not the secondary structure.
4. Consider the role of hydrogen bonds, which often stabilize secondary structures like α-helices by forming between the carbonyl oxygen of one amino acid and the amide hydrogen of another.
5. Recognize that van der Waals interactions and disulfide bonds are not typically involved in the formation of α-helices; van der Waals interactions are weak and non-specific, while disulfide bonds are covalent and stabilize tertiary structures.

Key Concepts

Peptide Bonds

Peptide bonds are covalent bonds that link amino acids together in a protein. They form during a dehydration synthesis reaction, where the carboxyl group of one amino acid reacts with the amino group of another, releasing a molecule of water. While peptide bonds are crucial for the primary structure of proteins, they do not directly stabilize secondary structures like the α-helix.

Hydrogen Bonds

Hydrogen bonds are weak attractions that occur between a hydrogen atom covalently bonded to an electronegative atom and another electronegative atom. In the context of an α-helix, hydrogen bonds form between the carbonyl oxygen of one amino acid and the amide hydrogen of another, stabilizing the helical structure. This interaction is essential for maintaining the secondary structure of proteins.

Secondary Structure

Secondary structure refers to the local folded structures that form within a protein due to interactions between the backbone atoms. Common types include α-helices and β-sheets, which are stabilized by hydrogen bonds. Understanding secondary structure is vital for grasping how proteins achieve their functional shapes and how these shapes relate to their biological roles.