Proline is the least common amino acid in α-helices due to its inability to fully participate in intrahelical hydrogen bonding.

Question

Quizplus · Accepted Answer

Proline's side chain is fused to its amine group, which creates a rigid ring structure that prevents it from participating in intrahelical hydrogen bonding. This limits its ability to form stable α-helices, making it the least commonly found amino acid in this secondary structure.

Proline Is the Least Common Amino Acid in α-Helices Due