title: Charge Transfer Dissociation (CTD) Mass Spectrometry of Peptide Cations: Study of Charge State Effects and Side-Chain Losses.
abstract: 1+, 2+, and 3+ precursors of substance P and bradykinin were subjected to helium cation irradiation in a 3D ion trap mass spectrometer. Charge exchange with the helium cations produces a variety of fragment ions, the number and type of which are dependent on the charge state of the precursor ions. For 1+ peptide precursors, fragmentation is generally restricted to C-CO backbone bonds (a and x ions), whereas for 2+ and 3+ peptide precursors, all three backbone bonds (C-CO, C-N, and N-Cα) are cleaved. The type of backbone bond cleavage is indicative of possible dissociation channels involved in CTD process, including high-energy, kinetic-based, and ETD-like pathways. In addition to backbone cleavages, amino acid side-chain cleavages are observed in CTD, which are consistent with other high-energy and radical-mediated techniques. The unique dissociation pattern and supplementary information available from side-chain cleavages make CTD a potentially useful activation method for the structural study of gas-phase biomolecules. Graphical Abstract ᅟ.
authors.affiliation: C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA.
authors.forename: Pengfei
authors.initials: P
authors.lastname: Li
authors.affiliation: C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA. glen.jackson@mail.wvu.edu.|Department of Forensic and Investigative Science, West Virginia University, Morgantown, WV, 26506-6121, USA. glen.jackson@mail.wvu.edu.
authors.forename: Glen P
authors.initials: GP
authors.lastname: Jackson
keywords: Charge transfer; Electron transfer; Ion/ion reaction; Peptide fragmentation; Radical ion