Natural Structural Motifs that Suppress Peptide Ion Fragmentation after Electron Capture
In: Journal of the American Society for Mass Spectrometry, Jg. 21 (2010-07-01), Heft 7, S. 1235-1244
Online
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Zugriff:
Series of doubly and triply protonated diarginated peptide molecules with different number of glutamic acid (E) and asparagine (N) residues were analyzed under ECD conditions. ECD spectra of doubly-protonated peptides show a strong dependence on the number of E and N residues. Both the backbone cleavages and hydrogen radical (H•) loss from the charge-reduced precursor ions ([M+2H]+•) were suppressed as the number of E and N residues increases. A strong inhibition of the backbone cleavages and H• loss from [M+2H]+• was found for peptides with 6E residues (or 4E + 2N residues). The results obtained using these model peptides were re-confirmed by analyzing N-arginated Fibrinopeptide-B (i.e., REGVNDNEEGFFSAR). In contrast to the N-arginated peptide, ECD of the doubly-protonated Fibrinopeptide-B and its analogues show extensive backbone cleavages leading to series of c- and z-ions (∼80% sequence coverage). Based on these results, it is believed that peptide ions with all surplus protons sequestered in arginine-residues would show enhanced stability under ECD conditions as the number of acid-residue increases. The suppression of backbone cleavages and H• loss from [M+2H]+• are presumably attributed to the low reactivity of the charge-reduced precursor ions. One of the possible hypothesis is that diarginated E-rich peptides may contain hydrogen bonds between carbonyl oxygen of E side chains and backbone amide hydrogen. These hydrogen bonds would provide extra stabilization for [M+2H]+•. This is the first demonstration of natural structural motifs in peptides that would inhibit the backbone fragmentation of the charge-reduced peptide ions under ECD conditions. [Copyright &y& Elsevier]
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Natural Structural Motifs that Suppress Peptide Ion Fragmentation after Electron Capture
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Autor/in / Beteiligte Person: | Chan, Wai Yi Kelly ; Chan, Tak Wah Dominic |
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Zeitschrift: | Journal of the American Society for Mass Spectrometry, Jg. 21 (2010-07-01), Heft 7, S. 1235-1244 |
Veröffentlichung: | 2010 |
Medientyp: | academicJournal |
ISSN: | 1044-0305 (print) |
DOI: | 10.1016/j.jasms.2010.03.034 |
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