Protein α-Turns Recreated in Structurally Stable Small Molecules

摘要

About 30% of protein structure is composed of peptide helices. An ideal α-helix consists of repeating (classical) a-turns, each of 3.6 amino acids, with identical backbone dihedral angles (φ -58°, ψ -47°), and a 13-membered hydrogen-bonded ring (Figure 1). However, α-turns inproteins are not identical due to variations in consecutive (φ, ψ) angles that subtly alter peptide backbone shape, side chain orientation and helical pitch (Figure l). For example, a study of 460 proteins identified 9 distinctly different latum types, with very different (φ, ψ) angles.