title: Relative Quantification of Sites of Peptide and Protein Modification Using Size Exclusion Chromatography Coupled with Electron Transfer Dissociation.
abstract: One difficult problem in the analysis of peptide modifications is quantifying isomeric modifications that differ by the position of the amino acid modified. HPLC separation using C18 reverse phase chromatography coupled with electron transfer dissociation (ETD) in tandem mass spectrometry has recently been shown to be able to relatively quantify how much of a given modification occurs at each amino acid position for isomeric mixtures; however, the resolution of reverse phase chromatography greatly complicates quantification of isomeric modifications by ETD because of the chromatographic separation of peptides with identical modifications at different sequence positions. Using peptide oxidation as a model system, we investigated the use of size exclusion chromatography coupled with ETD fragmentation to separate peptide sequences. This approach allows for the benefits of chromatographic separation of peptide sequences while ensuring co-elution of modification isomers for accurate relative quantification of modifications using standard data-dependent acquisitions. Using this method, the relative amount of modification at each amino acid can be accurately measured from single ETD MS/MS spectra in a standard data-dependent acquisition experiment. Graphical Abstract ᅟ.
authors.affiliation: Complex Carbohydrate Research Center, University of Georgia, Athens, GA, 30602, USA.
authors.forename: Boer
authors.initials: B
authors.lastname: Xie
authors.affiliation: Department of Biomolecular Sciences, University of Mississippi, University, MS, 38677, USA. jsharp@olemiss.edu.
authors.forename: Joshua S
authors.initials: JS
authors.lastname: Sharp
mesh_terms: D000595:Amino Acid Sequence; D002850:Chromatography, Gel; D004583:Electrons; D010455:Peptides; D011499:Protein Processing, Post-Translational; D053719:Tandem Mass Spectrometry
chemical_list: D010455:Peptides
keywords: Electron transfer dissociation; Fast photochemical oxidation of proteins; Hydroxyl radical protein footprinting; Peptide modification; Size exclusion chromatography