Characterization of α‐ and γ‐glutamyl dipeptides by negative ion collision‐induced dissociation

Harrison, Alex G.

doi:10.1002/jms.515

Cited by 22 publications

(22 citation statements)

References 44 publications

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“…It is generally observed for protonated peptides that the only exchangeable hydrogens are those attached to heteroatoms [4,9]. For deprotonated peptides, however, some C-bonded hydrogens are also mobilized during the activation process [25][26][27]. The predominant backbone cleavage in the present study is an N-C ␣ cleavage at an Asp residue.…”

Section: Discussionmentioning

confidence: 50%

Hydrogen atom scrambling in selectively labeled anionic peptides upon collisional activation by MALDI tandem time-of-flight mass spectrometry

Bache

Rand

Roepstorff

et al. 2008

J. Am. Soc. Mass Spectrom.

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We have previously shown that peptide amide hydrogens undergo extensive intramolecular migration (i.e., complete hydrogen scrambling) upon collisional activation of protonated peptides (Jørgensen et al. J. Am. Chem. Soc. 2005, 127, 2785-2793. The occurrence of hydrogen scrambling enforces severe limitations on the application of gas-phase fragmentation as a convenient method to obtain information about the site-specific deuterium uptake for proteins and peptides in solution. To investigate whether deprotonated peptides exhibit a lower level of scrambling relative to their protonated counterparts, we have now measured the level of hydrogen scrambling in a deprotonated, selectively labeled peptide using MALDI tandem time-of-flight mass spectrometry. Our results conclusively show that hydrogen scrambling is prevalent in the deprotonated peptide upon collisional activation. The amide hydrogens . In comparison, deprotonated peptides have received much less attention, and the mechanistic details of their fragmentation behavior are less well understood. We and others have previously investigated the proton mobility in protonated peptides and proteins upon collision-induced dissociation (CID) [2][3][4][5][6][7][8][9][10][11][12]. Our studies were motivated by earlier reports claiming that CID could be used to determine site-specific incorporation of deuterium in the backbone amides of peptides that were deuterated in solution [13][14][15][16]. In these reports, it was suggested that the level of intramolecular migration of amide hydrogens ( 1 H/ 2 H) in the protonated, collisionally activated peptide was negligible. It is important to emphasize that negligible levels of hydrogen migration would dramatically improve the resolution of localizing deuterated sites by mass spectrometric analysis of peptides and proteins labeled in solution ( 1 H/ 2 H) exchange experiments. But recent results have demonstrated unequivocally that all backbone amide hydrogens are positionally randomized upon collisional activation in the gaseous protonated peptide (i.e., causing 100% hydrogen scrambling) [3,6,7,10]. This implies that protonation of amide nitrogens is a reversible process in the gaseous activated peptide, and that the mobile proton (or deuteron) samples all exchangeable sites before peptide bond cleavage. Interestingly, this also occurs in singly protonated peptides exhibiting a preferred site-selective cleavages at Asp residues, which are thought to be induced by a reduced proton mobility [6]. Deprotonated peptides are deficient in protons and it is thus reasonable to assume that such ions might exhibit a lower degree of hydrogen scrambling than their protonated counterparts. Furthermore, low-energy CID of deprotonated peptides often yield a fragment ion type (c-ion) that is observed only rarely in protonated peptides [17]. The c-ion is the N-terminal fragment ion that results from backbone N-C ␣ bond cleavage. As anionic peptides thus exhibit different fragmentation pathways (relative to their protonated counterparts) and they...

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Section: Discussionmentioning

confidence: 50%

Hydrogen atom scrambling in selectively labeled anionic peptides upon collisional activation by MALDI tandem time-of-flight mass spectrometry

Bache

Rand

Roepstorff

et al. 2008

J. Am. Soc. Mass Spectrom.

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“…The daughter ion at m/z 224 might be produced by hydrogen/deuterium back-exchange of d 1 -labeled ion m/z 225 in ion trap [34] or by loss of a molecule of CH 2 DOD through a interchange of carbon-bonded hydrogens with labile hydrogens during the fragmentation reactions. [35] Meanwhile, the (Fig. 3B, entry 2).…”

Section: Positive-ion Esi-ms N Of the Protonated N-map-aasmentioning

confidence: 96%

Formation of cyclic acylphosphoramidates in mass spectra of N‐monoalkyloxyphosphoryl amino acids using electrospray ionization tandem mass spectrometry

Gao

Bao

et al. 2010

J. Mass Spectrom.

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The fragmentation reactions of N-monoalkyloxyphosphoryl amino acids (N-MAP-AAs) were studied by electrospray ionization tandem mass spectrometry (ESI-MS). The sodiated cyclic acylphosphoramidates (CAPAs) were formed through a characteristic pentacoordinate phosphate participated rearrangement reaction in the positive-ion ESI-MS/MS and HR-MS/MS of N-MAP-AAs, in which the fragmentation patterns were clearly different from those observed in the corresponding ESI-MS/MS of N-dialkyloxyphosphoryl amino acids/peptides and N-phosphono amino acids. The formation of CAPAs depended on the chemical structures of N-terminal phosphoryl groups, such as alkyloxy group, negative charge and alkali metal ion. A possible integrated rearrangement mechanism for both P-N to P-O phosphoryl group migration and formation of CAPAs was proposed. The fragmentation patterns of CAPAs as novel intermediates in gas phase were also investigated. In addition, it was found that the formation of alpha-amino acid CAPAs was more favorable than beta- or gamma-CAPAs in gas phase, which was consistent with previous solution-phase experiments.

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“…In our initial study 18 of deprotonated peptides containing only H or alkyl side chains, we observed that there was more extensive sequence-specific fragmentation under low-energy CID conditions than under high-energy CID conditions. 21 We have extended these studies to deprotonated peptides containing phenylalanine 22 and to deprotonated peptides containing glutamic acid; 23 in both cases fragmentation reactions specific to the side chain functionality were observed. In the present work, we explore…”

Section: Introductionmentioning

confidence: 94%

Fragmentation reactions of deprotonated peptides containing proline. The proline effect

Harrison

Young

2005

J. Mass Spectrom.

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The collision-induced dissociation (CID) fragmentation reactions of a variety of deprotonated peptides containing proline have been studied in detail using MS(2) and MS(3) experiments, deuterium labelling and accurate mass measurements when necessary. The [M--H--CO(2)](-) (a(2)) ion derived from H-Pro-Xxx-OH dipeptides shows an unusual fragmentation involving loss of C(2)H(4); this fragmentation reaction is not observed for larger peptides. The primary fragmentation reactions of deprotonated tripeptides with an N-terminal proline are formation of a(3) and y(1) ions. When proline is in the central position of tripeptides, a(3), y(2) and y(1) ions are the primary fragmentation products of [M--H](-), while when the proline is in the C-terminal position, a(3)and y(1) ions are the major primary products. In the latter case, the a(3) ion fragments primarily to the ''b(2) ion; further evidence is presented that the ''b(2) ions have a deprotonated oxazolone structure. Larger deprotonated peptides having at least two amino acid residues N-terminal to proline show a distinct preference for cleavage of the amide bond N-terminal to proline to form, mainly, the appropriate y ion. This proline effect is compared and contrasted with the similar proline effect observed in the fragmentation of protonated peptides containing proline.

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Characterization of α‐ and γ‐glutamyl dipeptides by negative ion collision‐induced dissociation

Cited by 22 publications

References 44 publications

Hydrogen atom scrambling in selectively labeled anionic peptides upon collisional activation by MALDI tandem time-of-flight mass spectrometry

Hydrogen atom scrambling in selectively labeled anionic peptides upon collisional activation by MALDI tandem time-of-flight mass spectrometry

Formation of cyclic acylphosphoramidates in mass spectra of N‐monoalkyloxyphosphoryl amino acids using electrospray ionization tandem mass spectrometry

Fragmentation reactions of deprotonated peptides containing proline. The proline effect

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