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Elucidation and identification of amino acid containing membrane lipids using liquid chromatography/high‐resolution mass spectrometry
Author(s) -
Moore Eli K.,
Hopmans Ellen C.,
Rijpstra W. Irene C.,
Villanueva Laura,
Sinninghe Damsté Jaap S.
Publication year - 2016
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.7503
Subject(s) - chemistry , chromatography , high performance liquid chromatography , mass spectrometry , electrospray ionization , fatty acid , fragmentation (computing) , amino acid , tandem mass spectrometry , biochemistry , computer science , operating system
Rationale Intact polar lipids (IPLs) are the building blocks of cell membranes, and amino acid containing IPLs have been observed to be involved in response to changing environmental conditions in various species of bacteria. High‐performance liquid chromatography/mass spectrometry (HPLC/MS) has become the primary method for analysis of IPLs. Many glycerol‐free amino acid containing membrane lipids (AA‐IPLs), which are structurally different than abundant aminophospholipids, have not been characterized using HPLC/MS. This results in many lipids remaining unrecognized in IPL analysis of microbial cultures and environmental samples, hampering the study of their occurrence and functionality. Methods We analyzed the amino acid containing IPLs of a number of bacteria (i.e. Gluconobacter cerinus , Cyclobacterium marinus , Rhodobacter sphaeroides , and Pedobacter heparinus ) in order to decipher fragmentation pathways, and explore potential novel lipid structures using HPLC/electrospray ionization ion trap MS (HPLC/ESI‐IT‐MS) and HPLC/high‐resolution MS (HPLC/HRMS). Results We report differentiation between glutamine and lysine lipids with the same nominal masses, novel MS fragmentation pathways of cytolipin, the lipopeptides cerilipin and flavolipin, head group hydroxylated ornithine lipids, and the novel identification of cerilipin with a hydroxylated fatty acid. Conclusions Non‐glycerol AA lipids can be readily recognized as their fragmentation follows a clear pattern with initial dehydration or other loss from the head group, followed by fatty acid losses resulting in a diagnostic fragment ion. Higher level MS n and HRMS are valuable tools in characterizing AA lipid head group structural components. Copyright © 2016 John Wiley & Sons, Ltd.