Question

Stabilization of the secondary structure of proteins involves a major contribution of the:

• A. Covalent bonds
• B. Hydrogen bond
• C. Sulphite bonds
• D. S S bonds

Answer 1

The correct option is B Hydrogen bond

For stabilization of the secondary structure of proteins, there is a major contribution of the hydrogen bonds. Strands of proteins or peptides have distinct characteristic of secondary structure, dependent on hydrogen bonding. The two main types of secondary structure are the $\alpha$-helix and the $\beta$-sheet.
The $\alpha$-helix is a right-handed coiled strand. The side-chain substituents of the amino acid groups in an $\alpha$-helix extend to the outside. Hydrogen bonds form between the oxygen of the $C=O$ of each peptide bond in the strand and the hydrogen of the $N-H$ group of the peptide bond four amino acids below it in the helix.
The hydrogen bonding in a $\beta$-sheet is between strands (inter-strand) rather than within strands (intra-strand). The sheet conformation consists of pairs of strands lying side-by-side.