CHAR OF CARDIOLIPIN FROM ESCHERICHIA COLI BY ELECTROSPRAY IONIZATION WITH

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We report multiple-stage ion-trap (IT) mass spectrometric methods with electrospray ionization (ESI) for structural characterization of the [M - 2H + Na]- ion of cardiolipin (CL), a 1,3-bisphosphatidyl-sn-glycerol that consists of four fatty acyl chains and three glycerol backbones designated, namely, as A, B and central glycerol, respectively. Following CAD, the MS2-spectrum of the [M - 2H + Na]- ions of CL contains two prominent fragment ions resulting from the differential losses of the respective diacylglycerol moieties involving A or B glycerol. The tentative assignment of the two phosphatidyl moieties attached to the 1'- or 3'-position of the central glycerol is based on the observation that the ions arising from loss of the diacylglycerol moiety involving glycerol B (or A) is more abundant than that involving glycerol A (or B). The structures of the two ions, including the identities of the fatty acyl substituents and the position of fatty acyl substituents on the glycerol backbones (glycerol A and B) are determined by their MS3-spectra that comprise several sets of prominent ions informative for their determination. This method permits the structures of CL in a mixture isolated from Escherichia Coli, including species that consist of various isomers, to be unveiled in details.