Q) 3. Which of the following peptides is most likely to form -helix: A. LKENDESQRTMSE B. KHSLTEQLKSVTDS C. APGDDPGDQPGTS D. KEEDREQEKKKKEK The answer is B, but why? - C must be wrong = amino acid Gly (G) + Proline (P) --> helix breaker - D must be wrong = amino acid Lysine (K) + Arginine (R)--> +ve charge at pH 7 = prevent alpha-helix forming - Alaine (A) + Leucine (L) --> helix former.