Abstract
The analysis of the aromatic region of 1H and 13C NMR spectra of cyclolinopeptide A (cyclic nonapeptide with the sequence c—(Pro— Pro— Phe—Phe—Leu— Ile— Ile— Leu— Val— ), (CLA)) shows that Phe-3 and Phe-4 aromatic rings are oriented nearly perpendicularly to each other, forming edge-to-face pair. It signifies the strong limitation of the free rotation of aromatic residues, probably because of the steric hindrance exerted by proximal aliphatic side chains of CLA.