Structure Determination of an Immunopotentiator Peptide, Cinnamycin, Complexed with Lysophosphatidylethanolamine by ¹H-NMR

Abstract

The three-dimensional structure of a complex of cinnamycin, a 19-amino acid residue immunopotentiator peptide, and lysophosphatidylethanolamine was determined by ¹H-NMR. The complex was cylindrical in shape, 11 Å in diameter and 26 Å in length, excluding the acyl chain of the phospholipid. The peptide had a hydrophobic pocket surrounded by residues Phe-7 through Ala (S)-14 to bind to the head group of the ligand. Fitting of the head group to the hydrophobic pocket was so good that other than a glycerophosphoethanolamine head group would be unable to fit the pocket. The goodness of the fitting is compatible with the strict specificity of ligand binding of the peptide.