Question

Which of the following statements is TRUE?

a. Disulfide bonds are formed by the cross-linking of methionine residues.
b. Disulfide bonds are formed mainly in proteins that are retained within the cytosol.
c. Disulfide bonds stabilize but do not change a protein's final conformation.
d. Disulfide bonds are more common for intracellular proteins, compared to extracellular proteins.

Answer 1

The true statement is that disulfide bonds, formed between cysteine residues within a protein, stabilize but do not change the protein's final conformation.

Step-by-step explanation:

The true statement from the options provided is that disulfide bonds stabilize but do not change a protein's final conformation. Disulfide bonds are covalent linkages formed when two cysteine amino acid residues within a protein come in close proximity and undergo an oxidation reaction, where the sulfur atoms in their highly reactive sulfhydryl (-SH) groups form a cystine linkage.

These bonds are essential for stabilizing the tertiary structure of proteins, especially extracellular proteins, as they help the protein to maintain its structure under varying physical and chemical conditions. It is important to note that methionine residues do not form these bonds and that disulfide bonds are more common in extracellular than intracellular proteins because the oxidative environment outside the cell facilitates the formation of these bonds.