Question

which of the levels of protein structure is affected by the formation of disulfide bonds between cysteine residues?
select all that apply:
primary
secondary
tertiary
quaternary

Explanation:

• Tertiary structure: Disulfide bonds are covalent bonds that contribute to the folding of a single polypeptide chain into its three - dimensional tertiary structure. They help stabilize the overall shape of the protein by forming cross - links between cysteine residues in different parts of the polypeptide.
• Quaternary structure: In proteins with quaternary structure (composed of multiple polypeptide subunits), disulfide bonds can also form between cysteine residues on different subunits. This helps in holding the subunits together in the correct spatial arrangement.
• Primary structure: The primary structure is just the linear sequence of amino acids linked by peptide bonds. Disulfide bonds are not part of the primary structure definition.
• Secondary structure: Secondary structures (like alpha - helices and beta - sheets) are formed by hydrogen bonding within the polypeptide backbone. Disulfide bonds do not play a role in secondary structure formation.

Answer:

C. tertiary, D. quaternary