Question

You have just sequenced a new protein isolated from mice and observe that sulfur-containing cysteine residues occur at regular intervals. This finding is most consistent with which of the following claims about the protein?

A) The protein is hydrophobic
B) The protein has a quaternary structure
C) The protein is involved in red blood cell formation
D) The protein contains disulfide bonds

Answer 1

The regular occurrence of cysteine residues in a protein suggests the presence of disulfide bonds that stabilize the protein's structure.

Step-by-step explanation:

The finding that sulfur-containing cysteine residues occur at regular intervals in a newly sequenced protein from mice is most consistent with the claim that the protein contains disulfide bonds. Cysteine has a highly reactive sulfhydryl (SH) group that can be oxidized to form cystine when two cysteine molecules come together. This type of covalent bond, known as a disulfide bond (S-S), significantly stabilizes the protein's tertiary structure. Disulfide bonds can also influence the protein's quaternary structure by linking separate polypeptide chains.