title: Separation and characterization of oxidized isomeric lipid-peptide adducts by ion mobility mass spectrometry.
abstract: Phospholipids are major components of cell membranes and lipoprotein complexes. They are prone to oxidation by endogenous and exogenous reactive oxygen species yielding a large variety of modified lipids including small aliphatic and phospholipid bound aldehydes and ketones. These carbonyls are strong electrophiles that can modify proteins and, thereby, alter their structures and functions triggering various pathophysiological conditions. The analysis of lipid-protein adducts by liquid chromatography-MS is challenged by their mixed chemical nature (polar peptide and hydrophobic lipid), low abundance in biological samples, and formation of multiple isomers. Thus, we investigated traveling wave ion mobility mass spectrometry (TWIMS) to analyze lipid-peptide adducts generated by incubating model peptides corresponding to the amphipathic β1 sheet sequence of apolipoprotein B-100 with 1-palmitoyl-2-(oxo-nonanoyl)-sn-glycerophosphatidylcholine (PONPC). The complex mixture of peptides, lipids, and peptide-lipid adducts was separated by TWIMS, which was especially important for the identification of two mono-PONPC-peptide isomers containing Schiff bases at different lysine residues. Moreover, TWIMS separated structural conformers of one peptide-lipid adduct possessing most likely different orientations of the hydrophobic sn-1 fatty acyl residue and head group of PONPC, relative to the peptide backbone.
authors.affiliation: Institute of Bioanalytical Chemistry, Faculty of Chemistry and Mineralogy, Universität Leipzig, Leipzig, Germany.|Center for Biotechnology and Biomedicine, Universität Leipzig, Leipzig, Germany.
authors.forename: Ivana
authors.initials: I
authors.lastname: Milic
authors.affiliation: Waters GmbH, Eschborn, Germany.
authors.forename: Marc
authors.initials: M
authors.lastname: Kipping
authors.affiliation: Institute of Bioanalytical Chemistry, Faculty of Chemistry and Mineralogy, Universität Leipzig, Leipzig, Germany.|Center for Biotechnology and Biomedicine, Universität Leipzig, Leipzig, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Hoffmann
authors.affiliation: Institute of Bioanalytical Chemistry, Faculty of Chemistry and Mineralogy, Universität Leipzig, Leipzig, Germany.|Center for Biotechnology and Biomedicine, Universität Leipzig, Leipzig, Germany.
authors.forename: Maria
authors.initials: M
authors.lastname: Fedorova
mesh_terms: D053299:Apolipoprotein B-100 / Q000737:chemistry; D007536:Isomerism; D008055:Lipids / Q000737:chemistry*; D013058:Mass Spectrometry / Q000379:methods*; D008956:Models, Chemical; D010455:Peptides / Q000737:chemistry*; D010713:Phosphatidylcholines / Q000737:chemistry
chemical_list: C097369:1-palmitoyl-2-(9-oxononanoyl)-sn-glycero-3-phosphocholine; D053299:Apolipoprotein B-100; D008055:Lipids; D010455:Peptides; D010713:Phosphatidylcholines
keywords: 1-palmitoyl-2-(oxo-nonanoyl)-sn-glycerophosphatidylcholine (PONPC); Schiff base; ion mobility spectrometry (IMS); lipid peroxidation; protein modifications