Cα-C Backbone Fragmentation Dominates in Electron Detachment Dissociation of Gas‐Phase Polypeptide Polyanions
- 25 February 2005
- journal article
- research article
- Published by Wiley in Chemistry – A European Journal
- Vol. 11 (6), 1803-1812
- https://doi.org/10.1002/chem.200400806
Abstract
Fragmentation of peptide polyanions by electron detachment dissociation (EDD) has been induced by electron irradiation of deprotonated polypeptides [M−nH]n− with >10 eV electrons. EDD has been found to lead preferentially to a. and x fragment ions (CαC backbone cleavage) arising from the dissociation of oxidized radical anions [M−nH](n−1)−.. We demonstrate that CαC cleavages, which are otherwise rarely observed in tandem mass spectrometry, can account for most of the backbone fragmentation, with even-electron x fragments dominating over radical a. ions. Ab initio calculations at the B3 LYP level of theory with the 6-311+G(2 p,2 d)//6-31+G(d,p) basis set suggested a unidirectional mechanism for EDD (cleavage always N-terminal to the radical site), with a., x formation being favored over a, x. fragmentation by 74.2 kJ mol−1. Thus, backbone CαC bonds N-terminal to proline residues should be immune to EDD, in agreement with the observations. EDD may find application in mass spectrometry for such tasks as peptide sequencing and localization of labile post-translational modifications, for example, those introduced by sulfation and phosphorylation. EDD can now be performed not only in Fourier transform mass spectrometry, but also in far more widely used quadrupole (Paul) ion traps.Keywords
This publication has 51 references indexed in Scilit:
- Investigation of Noncovalent Interactions in Deprotonated Peptides: Structural and Energetic Competition between Aggregation and HydrationJournal of the American Chemical Society, 2004
- Negative ion mass spectra of Cys-containing peptides. The characteristic Cysγ backbone cleavage: a joint experimental and theoretical studyRapid Communications in Mass Spectrometry, 2004
- Mass spectrometry-based proteomicsNature, 2003
- Characterization of gp93, a Novel, Highly Heterogeneous Glycoprotein Present in Growth Cone MembranesJournal of Neurochemistry, 2002
- Electron capture dissociation of weakly bound polypeptide polycationic complexesRapid Communications in Mass Spectrometry, 2002
- Fragmentation Reactions of a2 Ions Derived From Deprotonated DipeptidesA Synergy Between Experiment and TheoryThe Journal of Physical Chemistry A, 2002
- Negative ion electrospray mass spectra of caerulein peptides: an aid to structural determinationRapid Communications in Mass Spectrometry, 2002
- Collision‐induced fragmentations of the (M‐H)− parent anions of underivatized peptides: An aid to structure determination and some unusual negative ion cleavagesMass Spectrometry Reviews, 2002
- Identification of self peptides bound to purified HLA-B27Nature, 1991
- Contributions of mass spectrometry to peptide and protein structureJournal of Mass Spectrometry, 1988