title: A new anti-MRSA antibiotic complex, WAP-8294A II. Structure characterization of minor components by ESI LCMS and MS/MS.
abstract: 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.
authors.affiliation: Wakamoto Pharmaceutical Co. Ltd., Kanagawa, Japan.
authors.forename: Azusa
authors.initials: A
authors.lastname: Kato
authors.forename: Haruhisa
authors.initials: H
authors.lastname: Hirata
authors.forename: Yoshitami
authors.initials: Y
authors.lastname: Ohashi
authors.forename: Kiyonaga
authors.initials: K
authors.lastname: Fujii
authors.forename: Kenji
authors.initials: K
authors.lastname: Mori
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Harada
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000302:isolation & purification; D047630:Depsipeptides / Q000737:chemistry* / Q000302:isolation & purification; D005285:Fermentation; D053528:Lysobacter / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects; D021241:Spectrometry, Mass, Electrospray Ionization; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000382:microbiology; D053719:Tandem Mass Spectrometry
chemical_list: D000900:Anti-Bacterial Agents; D047630:Depsipeptides; C116834:lotilibcin