Fragmentation of alpha-Radical Cations of Arginine-Containing Peptides

Journal Article · Thu Apr 01 04:00:00 EDT 2010 · Journal of the American Society for Mass Spectrometry, 21(4):511-521

DOI:https://doi.org/10.1016/j.jasms.2009.12.021· OSTI ID:981562

Laskin, Julia; Yang, Zhibo; Ng, Dominic C; Chu, Ivan K

Fragmentation pathways of peptide radical cations, M+, with well-defined initial location of the radical site were explored using collision-induced dissociation (CID) experiments. Peptide radical cations were produced by gas-phase fragmentation of CoIII(salen)-peptide complexes [salen = N,N´-ethylenebis (salicylideneaminato)]. Subsequent hydrogen abstraction from the -carbon of the side chain followed by Ca-C bond cleavage results in the loss of a neutral side chain and formation of an a-radical cation with the radical site localized on the a-carbon of the backbone. Similar CID spectra dominated by radical-driven dissociation products were obtained for a number of a-radicals when the basic arginine side chain was present in the sequence. In contrast, proton-driven fragmentation dominates CID spectra of a-radicals produced via the loss of the arginine side chain. Our results suggest that in most cases radical migration precedes fragmentation of large peptide radical cations.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 981562
• Report Number(s): PNNL-SA-67259; 24494; KC0302020
• Journal Information: Journal of the American Society for Mass Spectrometry, 21(4):511-521, Journal Name: Journal of the American Society for Mass Spectrometry, 21(4):511-521 Journal Issue: 4 Vol. 21; ISSN 1044-0305; ISSN JAMSEF
• Country of Publication: United States
• Language: English

Related Subjects

08 HYDROGEN
ARGININE
BASIC
CARBON
CATIONS
CHAINS
CLEAVAGE
COMPLEXES
DISSOCIATION
Environmental Molecular Sciences Laboratory
FRAGMENTATION
HYDROGEN
MIGRATION
PEPTIDES
RADICALS
SPECTRA