Which of the following is a covalent interaction that is imp

Which of the following is a covalent interaction that is important in maintaining the secondary, tertiary, and quaternary structure of proteins?

            A. sulfur-sulfur bonds

            B. hydrogen bonding along the backbone

            C. hydrogen bonding between R groups

            D. salt bridges between R groups

            E. hydrophobic interactions between R groups

Solution

Hydrogen bonding along the backbone leads to formation of peptide bond, stabilizes secondary structures like alpha-helices and beta-sheets allows the exposed residues to interact with surrounding water molecules in the tertiary structure and also interaction between subunits in the quaternary structure.