Which of the Following Amino Acids is Unlikely to Be

Question

Which of the following amino acids is unlikely to be found in an α-helix?
A) phenylalanine
B) tryptophan
C) proline
D) lysine

Accepted Answer

Proline is unlikely to be found in an α-helix due to its unique structure. Proline's side chain forms a covalent bond with its amino group, creating a rigid structure that disrupts the regular hydrogen bonding pattern found in α-helices. This makes it difficult for proline to fit into the α-helix structure, so it is rarely found in this conformation.