Which of the Following Structural Proteins Is Correctly Paired with the Modified

Multiple Choice

Which of the following structural proteins is correctly paired with the modified amino acid or cross-link that is an integral part of that protein?

A) collagen: 5-hydroxylysine
B) elastin: hydroxyproline
C) $\alpha$ -keratin: cross link formed by oxidation of lysine, then aldol condensation
D) collagen: desmosine
E) fibroin: cross-link formed by dehydration of serine residues