A Novel, Antimicrobially Active Analog of Gramicidin S without Amphiphilic Conformation

Makoto Tamaki, Kenta Sawa, Sho Kikuchi, Mitsuno Shindo, Yoshiki Uchida

Received: March 10, 2006 / Accepted: May 29, 2006
© Japan Antibiotics Research Association

Abstract A novel gramicidin S analog, cyclo(-Val-Leu-Leu-Orn-Leu-d-Phe-Pro-)2, was synthesized, its antibiotic activity compared with gramicidin S and shown to be as potent as gramicidin S when compared with the susceptibility toward five Gram-positive microorganisms. It exceeded the activity of gramicidin S against Bacillus megaterium ATCC 19213 by a factor of two. Circular dichroism and NMR data suggested this analog to adopt an antiparallel β-sheet conformation without amphiphilic character.

Keywords gramicidin S analog, a potent cyclotetradecapeptide antibiotic, antiparallel β-sheet conformation, no amphiphilic character, circular dichroism, NMR

M. Tamaki (Corresponding author), K. Sawa, S. Kikuchi: Department of Chemistry, Toho University, Funabashi, Chiba 274-8510, Japan, Email:
M. Shindo, Y. Uchida: Department of Food Science and Nutrition, Osaka Shoin Women√‘ University, Higashi-Osaka, Osaka 577-8550, Japan