Molecular conformation of achatin‐I, an endogenous neuropeptide containing D‐amino acid residue

Abstract

The molecular conformation of achatin-I neutral form (H-Gly-D-Phe-Ala-Asp-OH), an endogenous neuropeptide, was elucidated by X-ray crystal analysis. The molecule has a type II' β-turn structure with the D-Phe-Ala residues at the corner of the bend, which is further stabilized by two NH(Gly)βC γ O δ (Asp) and NH(Asp)βC γ O δ (Asp) intramolecular hydrogen bonds. This turn conformation may be an important feature of achatin-I related to its neuroexcitatory activity.