Identification by mass spectrometry of glucosaminylphosphatidylglycerol, a phosphatidylglycerol derivative, produced by Pseudomonas aeruginosa. (11th November 2018)

• Record Type: Journal Article
• Authors: Abbes, Imen; Rihouey, Christophe; Hardouin, Julie; Jouenne, Thierry; De, Emmanuelle; Alexandre, Stéphane
• Is Part Of: Rapid communications in mass spectrometry. Volume 32:Number 24(2018)
• Page Start: 2113
• Page End: 2121
• Publication Date: 2018-11-11
• Subjects: Mass spectrometry -- Periodicals; 543.65
• DOI: 10.1002/rcm.8277
• Languages: English
• ISSNs: 0951-4198

Abstract

Abstract : Rationale: Pseudomonas aeruginosa is an opportunistic pathogen bacterium widely considered to be an excellent research model in several areas of molecular studies, namely genomics and proteomics. However, its lipid metabolism is still not totally decrypted. While it is known that this bacterium has the particularity to produce phosphatidylcholine, a lipid mainly found in eukaryotes, other singularities are still to be discovered. Methods: P. aeruginosa was grown as planktonic cultures to the stationary state. Membrane pellets were collected and lipids were extracted using the Bligh and Dyer protocol. Lipid extracts were analyzed by Electrospray Ionization Mass Spectrometry (ESI‐MS) using high‐resolution mass spectrometer (LTQ Orbitrap Elite, Thermo Scientific) in the negative mode. MS n spectra were recorded both in the Orbitrap and in the ion trap analyzer (collision‐induced dissociation (CID) or higher energy collision‐induced dissociation (HCD) mode). Results: We observed by mass spectrometry and thin layer chromatography that P. aeruginosa produced an unreferenced lipid in classical growth conditions. MS 2 analysis of the unknown ion indicates that it is a phosphatidylglycerol derivative. The exact mass shift corresponds to glucosamine which is largely found in the metabolism of this bacterium. MS 3 analysis of secondary ions allowed us to conclude that this lipid is a glucosaminylphosphatidylglycerol, a phosphatidylglycerol derivative containing a glucosamine substituted at C4. Conclusions: We show here that P. aeruginosa is able to produce glucosaminylphosphatidylglycerols via a probable esterification of phosphatidylglycerols by glucosamine.