lotilibcin and Staphylococcal-Infections

The anti-MRSA antibiotic, WAP-8294A, was isolated from the fermentation broth of Lysobacter sp. The major component, WAP-8294A2, is composed of 1 mol of Gly, L-Leu, L-Glu, D-Asn, D-Trp, D-threo-β-hydroxyasparagine, N-Me-D-Phe and N-Me-L-Val, and 2 mol of L-Ser, D-Orn and D-3-hydroxy-7-Me-octanoic acid. The structure of the WAP-8294A2 was mainly determined as a cyclic depsipeptide by 2D NMR experiments. However, it was difficult to use the NMR experiment to determine the minor components, A1, A4 and Ax13, isolated in small amounts. In the present study, ESI MS/MS was applied to the structure elucidation of these minor components. The structures of these minor components were determined on the basis of the fragmentation pattern of the product ions of WAP-8294A2 in the ESI MS/MS. As a result, it was confirmed that A1 and A4 had the same amino acid sequence as A2, while A1 and A4 had the 3-OH-octanoic acid and 3-OH-8-Me-nonanoic acid, respectively, in the place of the 3-OH-7-Me-octanoic acid in A2. In the structure of Ax13, it was found that Gly of A2 was changed to β-Ala of Ax13.

Topics: Amino Acid Sequence; Anti-Bacterial Agents; Depsipeptides; Fermentation; Lysobacter; Magnetic Resonance Spectroscopy; Methicillin-Resistant Staphylococcus aureus; Spectrometry, Mass, Electrospray Ionization; Staphylococcal Infections; Tandem Mass Spectrometry

WAP-8294A, produced by Lysobacter sp., is a complex consisting of water soluble depsipeptide antibiotics. It was further purified by column chromatographies and HPLC, and 19 components were obtained. WAP-8294A2, a major component, and minor components A1, A4, Ax8, Ax9 and Ax13 were active against gram-positive bacteria, in particular, methicillin-resistant Staphylococcus aureus (MRSA) in vitro. WAP-8294A2 was highly active in vivo in mice against the systemic infection of MRSA.

Topics: Animals; Anti-Bacterial Agents; Depsipeptides; Fermentation; Fungi; Gram-Negative Bacteria; Gram-Positive Bacteria; Inhibitory Concentration 50; Leukemia L1210; Macrolides; Magnetic Resonance Spectroscopy; Male; Mass Spectrometry; Methicillin Resistance; Mice; Mice, Inbred ICR; Microbial Sensitivity Tests; Peptides, Cyclic; Staphylococcal Infections; Staphylococcus aureus; Tumor Cells, Cultured