title: Analysis of covalent modifications of proteins by oxidized phospholipids using a novel method of peptide enrichment.
abstract: Free radical-induced oxidation of phospholipids contributes significantly to pathologies associated with inflammation and oxidative stress. Detection of covalent interaction between oxidized phospholipids (oxPL) and proteins by LC-MS/MS could provide valuable information about the molecular mechanisms of oxPL effects. However, such studies are very limited because of significant challenges in detection of the comparatively low levels of oxPL-protein adducts in complex biological systems. Current approaches have several limitations, most important of which is the inability to detect protein modifications by naturally occurring oxPL. We now report, for the first time, an enrichment method that can be applied to the global analysis of protein adducts with various naturally occurring oxPL in relevant biological systems. This method exploits intrinsic properties of peptides modified by oxPL, allowing highly efficient enrichment of oxPL-modified peptides from biological samples. Very low levels of oxPL-protein adducts (<2 ppm) were detected using this enrichment method in combination with LC-MS/MS. We applied the method to several model systems, including oxidation of high density lipoprotein (HDL) and interaction of human platelets with a specific oxPL, and demonstrated its extremely high efficiency and productivity. We report multiple new modifications of apolipoproteins in HDL and proteins in human platelets.
authors.affiliation: Department of Molecular Cardiology, Cleveland Clinic, Lerner Research Institute , Cleveland, Ohio 44195, United States.
authors.forename: Detao
authors.initials: D
authors.lastname: Gao
authors.forename: Belinda
authors.initials: B
authors.lastname: Willard
authors.forename: Eugene A
authors.initials: EA
authors.lastname: Podrez
mesh_terms: D000595:Amino Acid Sequence; D001792:Blood Platelets / Q000737:chemistry; D001798:Blood Proteins / Q000737:chemistry*; D002853:Chromatography, Liquid; D006801:Humans; D008075:Lipoproteins, HDL / Q000737:chemistry*; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010455:Peptides / Q000032:analysis*; D010743:Phospholipids / Q000737:chemistry*; D059748:Proteolysis; D053719:Tandem Mass Spectrometry; D014357:Trypsin / Q000737:chemistry
chemical_list: D001798:Blood Proteins; D008075:Lipoproteins, HDL; D010455:Peptides; D010743:Phospholipids; D014357:Trypsin