title: Structural analysis of lipid A from Escherichia coli O157:H7:K- using thin-layer chromatography and ion-trap mass spectrometry.
abstract: Rapid separation and structural identification of lipid A from Escherichia coli were performed using thin-layer chromatography (TLC) and mass spectrometry (MS). After the resolved spot of the lipid A had been scraped from TLC plate, the sample was re-extracted from the removed powder with chloroform-methanol (2 : 1, v/v) and analyzed by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) and electrospray ionization (ESI) ion-trap MS. For detailed structural characterization, multiple-stage mass analysis (MS(4)) of the major species in ESI-MS/MS provided important information about the series of fragment ions. The dominant fragment ions in each MS stage were produced from the loss of fatty acyl groups mainly driven by charge-remote processes, and this information about the fragment ions can be used to deduce the composition or the position of the fatty acid substituent in the lipid A. In contrast, MALDI-TOFMS indicated that fragmentation resulted from charge-driven processes. Molecular mass profiling and fragmentation analysis provides essential information for clarifying the detailed structure of the lipid A from E. coli O157:H7:K(-).
authors.affiliation: School of Chemical Engineering and Institute of Molecular Biology and Genetics, Seoul National University, Kwanak-Gu, Seoul 151-742, Korea.
authors.forename: Chang-Soo
authors.initials: CS
authors.lastname: Lee
authors.forename: Yun-Gon
authors.initials: YG
authors.lastname: Kim
authors.forename: Hwang-Soo
authors.initials: HS
authors.lastname: Joo
authors.forename: Byung-Gee
authors.initials: BG
authors.lastname: Kim
mesh_terms: D002855:Chromatography, Thin Layer; D019453:Escherichia coli O157 / Q000737:chemistry*; D005227:Fatty Acids / Q000032:analysis / Q000737:chemistry; D008050:Lipid A / Q000737:chemistry* / Q000302:isolation & purification; D013058:Mass Spectrometry; D015394:Molecular Structure
chemical_list: D005227:Fatty Acids; D008050:Lipid A