Question

Why is proline commonly found in beta turns?

Answer 1

Beta turn or beta bend are a type of secondary structure of protein. In a beta turn, a tight loop is formed when the carbonyl oxygen of one amino acid forms a hydrogen bond with the amide proton of an amino acid three residues down the chain. This hydrogen bond stabilizes the beta bend structure. For this purpose, proline is frequently found in beta turns, because its cyclic structure is ideally suited for the beta turn. Except proline, glycines are also common at amino acids with positive Fi angles.