Synthesis of [4-5,4′-5′-Bis(δ-Aminovaleric Acid)]-Gramicidin S

Abstract

Abstract An analog of gramicidin S, [4-5,4′-5′’-bis(δ-aminovaleric acid)]-gramicidin S, was synthesized, in which both of the two residues of d-Phe-l-Pro of gramicidin S (GS) were replaced with δ-aminovaleric acid residues (δAva). The spectra of optical rotatory dispersion (ORD) and circular dichroism (CD) of this analog suggest that its conformation in solution at room temperature is a random structure by comparison with that of GS. This analog has no antimicrobial activity. The linear peptide H-(Val-Orn-Leu-δAva-)2-OH also has no activity and its ORD and CD are nearly the same as those exhibited by the random structure of the polypeptide. These results indicate the importance of the presence of d-Phe-l-Pro in GS for the maintenance of the specific conformation.