Total Synthesis, Functional Analysis and Biological Evaluation of Antibiotic Peptide Natural Products

摘要

Recently, a novel antimicrobial agent lysocin E (1, Figure la) was isolated from a culture supernatant of a lysobacter species by Sekimizu and co-workers, and was showed to be effective against Gram-positive bacteria including methicillin-resistant Staphylococcus aureus (MRSA) [1]. Peptide 1 had potent antibiotic activity in mouse infection model with ED50 value of 0.6 mg/kg. Therefore, this compound is considered as a promising candidate for treatment of multidrug resistant bacterial infection. The structure of 1 is featured by a 37-membered macrocycle, five D-amino acid residues, N-methylation on peptide main chain, and C7 fatty acid moiety. Peptide 1 was suspected to target menaquinone-4 (Figure lb), which is an essential component of the electron transport system on bacterial membranes, and to dissipate the membrane structure in S. aureus. In order to investigate further mechanism of action of 1, the total synthesis and structure-function relationship study were performed.