Free Radical-Induced Site-Specific Peptide Cleavage in the Gas Phase : Low-Energy Collision-Induced Dissociation in ESI- and MALDI Mass Spectrometry

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Author(s)

  • Huiyong Yin
  • Almary Chacon
  • Ned A. Porter
  • Douglas S. Masterson

Detail(s)

Original languageEnglish
Pages (from-to)807-816
Journal / PublicationJournal of the American Society for Mass Spectrometry
Volume18
Issue number5
Publication statusPublished - May 2007
Externally publishedYes

Abstract

Protein identification is routinely accomplished by peptide sequencing using mass spectrometry (MS) after enzymatic digestion. Site-specific chemical modification may improve peptide ionization efficiency or sequence coverage in mass spectrometry. We report herein that amino group of lysine residue in peptides can be selectively modified by reaction with a peroxycarbonate and the resulting lysine peroxycarbamates undergo homolytic fragmentation under conditions of low-energy collision-induced dissociation (CID) in electrospray ionization (ESI) and matrix-assisted laser desorption and ionization (MALDI) MS. Selective modification of lysine residue in peptides by our strategy can induce specific peptide cleavage at or near the lysine site. Studies using deuterated analogues of modified lysine indicate that fragmentation of the modified peptides involves apparent free-radical processes that lead to peptide chain fragmentation and side-chain loss. The formation of a-, c-, or z-types of ions in MS is reminiscent of the proposed free-radical mechanisms in low-energy electron capture dissociation (ECD) processes that may have better sequence coverage than that of the conventional CID method. This site-specific cleavage of peptides by free radical- promoted processes is feasible and such strategies may aid the protein sequencing analysis and have potential applications in top-down proteomics. © 2007 American Society for Mass Spectrometry.

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Citation Format(s)

Free Radical-Induced Site-Specific Peptide Cleavage in the Gas Phase: Low-Energy Collision-Induced Dissociation in ESI- and MALDI Mass Spectrometry. / Yin, Huiyong; Chacon, Almary; Porter, Ned A. et al.
In: Journal of the American Society for Mass Spectrometry, Vol. 18, No. 5, 05.2007, p. 807-816.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review