A54145, A NEW LIPOPEPTIDE ANTIBIOTIC COMPLEX: ISOLATION AND CHARACTERIZATION

Abstract

A54145 is a complex of acidic lipopeptide antibiotics which are produced by Streptomyces fradiae and are active against Gram-positive bacteria. The A54145 complex was isolated by adsorption on Diaion HP-20 nonfunctionalized macroreticular resin and/or ion exchange on Amberlite IRA-68 anion exchange resin. Antibacterial factors A, A₁, B, B₁, C, D, E, and F were obtained in purified form by repeated preparative reverse phase HPLC on C₈ and/or C₁₈ bonded-phase supports. The molecular formulae of the factors are C₇₂H₁₀₉N₁₇O₂₇ (factors A and A₁), C₇₃H₁₁₁N₁₇O₂₇ (factors B, B₁, C, and D), C₇₄H₁₁₃N₁₇O₂₇ (factor E), and C₇₁H₁₀₇N₁₇O₂₇ (factor F). The identities of the acyl side chains were established as 8-methylnonanoyl (factors F, A, and B₁), n-decanoyl (factors A₁ and B), and 8-methyldecanoyl (factors C, D, and E).