Characterization of Ornithine and Glutamine Lipids Extracted from Cell Membranes of Rhodobacter sphaeroides

• Published in: Journal of the American Society for Mass Spectrometry Vol. 20; no. 2; pp. 198 - 212
• Main Authors: Zhang, Xi, Ferguson-Miller, Shelagh M., Reid, Gavin E.
• Format: Journal Article
• Language: English
• Published: New York Elsevier Inc 01.02.2009; Springer-Verlag; Elsevier; Springer Nature B.V
• Subjects: Analytical Chemistry; Bacteriology; Bioinformatics; Biological and medical sciences; Biotechnology; Cell Membrane - chemistry; Cell membranes; Chains; Chemistry; Chemistry and Materials Science; Deuterium; Fragmentation; Fundamental and applied biological sciences. Psychology; Glutamine; Glutamine - chemistry; Glycerylphosphorylcholine - deficiency; Ions; Lipids; Lipids - chemistry; Mass spectrometry; Membranes; Microbiology; Morphology, structure, chemical composition; Multistage; Organic Chemistry; Ornithine - analogs & derivatives; Ornithine - chemistry; Proteomics; Quadrupoles; Quantitative analysis; Rhodobacter sphaeroides - chemistry; Rhodobacter sphaeroides - genetics; Rhodobacter sphaeroides - ultrastructure; Spectrometry, Mass, Electrospray Ionization - methods; Structural analysis; Tandem Mass Spectrometry - methods; LIPIDOME Analysis; Fatty Acyl Chain; Rhodobacter Sphaeroides; Collision Induce Dissociation; Ornithine; Tandem mass spectrometry; Lipids; Rhodospirillaceae; Fatty acids; Electrospray; Quadrupole spectrometer; α-Aminoacid; Rhodospirillales; Ion trap; Analysis method; Rhodobacter sphaeroides; Plasma membrane; Bacteria; Carboxamide; Mutation; Rhodospirillineae; Acylate; Structural analysis
• ISSN: 1044-0305; 1879-1123
• DOI: 10.1016/j.jasms.2008.08.017

The identification and structural characterization of a series of ornithine lipids extracted from the cell membranes of wild-type Rhodobacter sphaeroides, as well as from a glycerophosphocholine-deficient strain, have been achieved by multistage tandem mass spectrometry of their protonated and deprotonated precursor ions in a linear quadrupole ion trap. Systematic examination of the multistage gas-phase fragmentation reactions of these ions, combined with the use of hydrogen/deuterium exchange, has enabled the pathways responsible for sequential losses of the 3-hydroxy linked fatty acyl chain and the amide linked 3-OH fatty acyl chain from these lipids, as well as for formation of the previously reported ornithine specific positively charged “fingerprint” ion at m/z 115, to be determined. Additionally, the fragmentation pathways responsible for formation of a previously unreported ornithine lipid head group-specific product ion at m/z 131 in negative ion mode have been examined. Based on these results, and by comparison with the fragmentation behavior of model lipoamino acid standard compounds, a series of novel glutamine containing lipids have also been identified, with analogous structures but with masses 14 Da higher than those of several of the ornithine lipids observed in this study. Characteristic “fingerprint” ions indicative of these glutamine lipids were found at m/z 147, 130, and 129 in positive ion mode and at m/z 145 and 127 in negative ion mode. The results from this study establish an experimental basis for future efforts aimed at the sensitive identification, characterization, and quantitative analysis of ornithine and glutamine lipids in complex unfractionated cellular extracts. Multistage MS/MS identifies head group specific “fingerprint” ions for a series of ornithine lipids and novel glutamine lipids from cell membranes of Rhodobacter sphaeroides.