Comparative analysis of ceramide structural modification found in fungal cerebrosides by electrospray tandem mass spectrometry with low energy collision-induced dissociation of Li+ adduct ions

Comparative analysis of ceramide structural modification found in fungal cerebrosides by electrospray tandem mass spectrometry with low energy collision-induced dissociation of Li+ adduct ions

Autor Levery, S. B. Google Scholar
Toledo, M. S. Google Scholar
Doong, R. L. Google Scholar
Straus, A. H. Google Scholar
Takahashi, H. K. Google Scholar
Instituição Univ Georgia
Universidade Federal de São Paulo (UNIFESP)
Resumo Fungal cerebrosides (monohexosylceramides, or CMHs) exhibit a number of ceramide structural modifications not found in mammalian glycosphingolipids, which present additional challenges for their complete characterization. the use of Li+ cationization, in conjunction with electrospray ionization mass spectrometry and low energy collision-induced dissociation tandem mass spectrometry (ESI-MS/CID-MS), was found to be particularly effective for detailed structural analysis of complex fungal CMHs, especially minor components present in mixtures at extremely low abundance. A substantial increase in both sensitivity and fragmentation was observed on collision-induced dissociation of [M + Li](+) versus [M + Na](+) of the same CMH components analyzed under similar conditions. the effects of particular modifications on fragmentation were first systematically evaluated by analysis of a wide variety of standard CMHs expressing progressively more functionalized ceramides, These included bovine brain galactocerebrosides with non-hydroxy and 2-hydroxy fatty N-acylation; a plant glucocerebroside having (E/Z)-Delta(8) in addition to (E)-Delta(4) unsaturation of the sphingoid base; and a pair of fungal cerebrosides known to be further modified by a branching 9-methyl group on the sphingoid moiety, and to have a 2-hydroxy fatty N-acyl moiety either fully saturated or (E)-Delta(3) unsaturated. the method was then applied to characterization of both major and minor components in CMH fractions from a non-pathogenic mycelial fungus, Aspergillus niger; and from pathogenic strains of Candida albicans (yeast form); three Cryptococcus spp. (all yeast forms); and Paracoccidioides brasiliensis (both yeast and mycelium forms). the major components of all species examined differed primarily (and widely) in the level of 2-hydroxy fatty N-acyl Delta(3) unsaturation, but among the minor components a significant degree of additional structural diversity was observed, based on differences in sphingoid or N-acyl chain length, as well as on the presence or absence of the sphingoid Bs unsaturation or 9-methyl group. Some variants were isobaric, and were not uniformly present in all species, affirming the need for MS/CID-MS analysis for full characterization of all components in a fungal CMH fraction. the diversity in ceramide distribution observed may reflect significant species-specific differences among fungi with respect to cerebroside biosynthesis and function. Copyright (C) 2000 John Wiley & Sons, Ltd.
Idioma Inglês
Data de publicação 2000-01-01
Publicado em Rapid Communications in Mass Spectrometry. W Sussex: John Wiley & Sons Ltd, v. 14, n. 7, p. 551-563, 2000.
ISSN 0951-4198 (Sherpa/Romeo, fator de impacto)
Publicador Wiley-Blackwell
Extensão 551-563
Fonte http://dx.doi.org/10.1002/(SICI)1097-0231(20000415)14:7<551
Direito de acesso Acesso restrito
Tipo Artigo
Web of Science WOS:000086139800002
Endereço permanente http://repositorio.unifesp.br/handle/11600/26208

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