Characteristic NH<sub>3</sub> and CO losses from sodiated peptides <i>C</i>‐terminated by glutamine residues

Guan, Xinshu; Wang, Bing; Wang, Huixin; Liu, Jinrong; Liu, Ying; Guo, Xinhua

doi:10.1002/rcm.7831

Cited by 3 publications

(3 citation statements)

References 38 publications

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“…S28). Thus, the concomitant loss of NH 3 and CO is involved in this process, which is different from the two-step characteristic losses of NH 3 and CO from the C-terminal Gln residue of sodiated peptides 20 . Additionally, the chemical identity of this fragment was confirmed using MS/MS analysis of [Gln-d 5 + D] + , in which it shifted to m/z 105.07370 by a concomitant loss of ND 3 and CO (Supplementary Fig.…”

Section: Resultsmentioning

confidence: 80%

Revisiting Fragmentation Reactions of Protonated α-Amino Acids by High-Resolution Electrospray Ionization Tandem Mass Spectrometry with Collision-Induced Dissociation

Zhang

Chan

Ang

et al. 2019

Sci Rep

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Fragmentation reactions of protonated α-amino acids (AAs) were studied previously using tandem mass spectrometry (MS/MS) of unit mass resolution. Isobaric fragmentation products and minor fragmentation products could have been overlooked or misannotated. In the present study, we examined the fragmentation patterns of 19 AAs using high-resolution electrospray ionization MS/MS (HR-ESI-MS/MS) with collision-induced dissociation (CID). Isobaric fragmentation products from protonated Met and Trp were resolved and identified for the first time. Previously unreported fragmentation products from protonated Met, Cys, Gln, Arg, and Lys were observed. Additionally, the chemical identity of a fragmentation product from protonated Trp that was incorrectly annotated in previous investigations was corrected. All previously unreported fragmentation products and reactions were verified by pseudo MS 3 experiments and/or MS/MS analyses of deuterated AAs. Clearer pictures of the fragmentation reactions for Met, Cys, Trp, Gln, Arg and Lys were obtained in the present study.

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Section: Resultsmentioning

confidence: 80%

Revisiting Fragmentation Reactions of Protonated α-Amino Acids by High-Resolution Electrospray Ionization Tandem Mass Spectrometry with Collision-Induced Dissociation

Zhang

Chan

Ang

et al. 2019

Sci Rep

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“…Various mass spectrometry (MS) studies have focused on the loss of small neutral molecules from protonated peptides containing asparagine (Asn) and glutamine (Gln). − Deamidation reactions of Asn and Gln have been the focus of significant attention, inspired by the spontaneous post-translational deamidation processes in proteins. These processes are believed to play a role in several diseases such as Alzheimer’s and Parkinson’s but also in aging effects for which it acts as a molecular clock. − Furthermore, the deamidation rates of several peptides containing Asn have been investigated and vary over 3–4 orders of magnitude .…”

Section: Introductionmentioning

confidence: 99%

Deamidation of Protonated Asparagine–Valine Investigated by a Combined Spectroscopic, Guided Ion Beam, and Theoretical Study

et al. 2018

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Peptide deamidation of asparaginyl residues is a spontaneous post-translational modification that is believed to play a role in aging and several diseases. It is also a well-known small-molecule loss channel in the MS/MS spectra of protonated peptides. Here we investigate the deamidation reaction, as well as other decomposition pathways, of the protonated dipeptide asparagine–valine ([AsnVal + H]+) upon low-energy activation in a mass spectrometer. Using a combination of infrared ion spectroscopy, guided ion beam tandem mass spectrometry, and theoretical calculations, we have been able to identify product ion structures and determine the energetics and mechanisms for decomposition. Deamidation proceeds via ammonia loss from the asparagine side chain, initiated by a nucleophilic attack of the peptide bond oxygen on the γ-carbon of the Asn side chain. This leads to the formation of a furanone ring containing product ion characterized by a threshold energy of 129 ± 5 kJ/mol (15 kJ/mol higher in energy than dehydration of [AsnVal + H]+, the lowest energy dissociation channel available to the system). Competing formation of a succinimide ring containing product, as has been observed for protonated asparagine–glycine ([AsnGly + H]+) and asparagine–alanine ([AsnAla + H]+), was not observed here. Quantum-chemical modeling of the reaction pathways confirms these subtle differences in dissociation behavior. Measured reaction thresholds are in agreement with predicted theoretical reaction energies computed at several levels of theory.

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“…Studies of gas-phase fragmentation reactions of protonated amino acids, particularly in collision-induced fragmentation (CID), are crucial not only for their identification and quantification but also for facilitating the understanding of the fragmentation reactions of its analogous and small peptides [1,2,3,4]. Cystine, an oxidized form of cysteine, is a special dimer of cysteine.…”

Section: Introductionmentioning

confidence: 99%

Gas-Phase Fragmentation Reactions of Protonated Cystine using High-Resolution Tandem Mass Spectrometry

et al. 2019

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Cystine is an important biomolecule in living systems. Although collision-induced dissociation (CID)-based tandem mass spectrometry (MS/MS) is commonly applied for identification and quantification of cystine in both biomedical and nutritional studies, gas-phase fragmentation reactions of cystine in CID has remained unclear. This may lead to improper assay design, which may in turn result in inaccurate test results. In the present study, gas-phase fragmentation reactions of protonated cystine in CID were characterized using high-resolution MS/MS and pseudo MS3. Fragmentations started from cleavages of disulfide bond (S–S) and carbon–sulfur bond (C–S). When cleaving at the S–S, protonated cysteine was generated as one of the predominant fragmentation products. Minor fragmentations started from the loss of H2O + CO and the loss of NH3. Our results reveal that the m/z 74 fragment ion, which is commonly used as a product ion of the transition (precursor/product ion pair) in selected reaction monitoring (SRM) assay for quantifying cystine, comprises two isobaric fragments originating from different parts of cystine. This indicates the need for careful selection of a stable isotope-labeled cystine molecule as an internal standard for SRM assays. Here, we provide a clear picture of the fragmentation reactions of protonated cystine in CID. It can serve as a useful guidance for designing MS/MS-based assays for cystine testing.

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Characteristic NH₃ and CO losses from sodiated peptides C‐terminated by glutamine residues

Cited by 3 publications

References 38 publications

Revisiting Fragmentation Reactions of Protonated α-Amino Acids by High-Resolution Electrospray Ionization Tandem Mass Spectrometry with Collision-Induced Dissociation

Revisiting Fragmentation Reactions of Protonated α-Amino Acids by High-Resolution Electrospray Ionization Tandem Mass Spectrometry with Collision-Induced Dissociation

Deamidation of Protonated Asparagine–Valine Investigated by a Combined Spectroscopic, Guided Ion Beam, and Theoretical Study

Gas-Phase Fragmentation Reactions of Protonated Cystine using High-Resolution Tandem Mass Spectrometry

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Characteristic NH3 and CO losses from sodiated peptides C‐terminated by glutamine residues

Cited by 3 publications

References 38 publications

Revisiting Fragmentation Reactions of Protonated α-Amino Acids by High-Resolution Electrospray Ionization Tandem Mass Spectrometry with Collision-Induced Dissociation

Revisiting Fragmentation Reactions of Protonated α-Amino Acids by High-Resolution Electrospray Ionization Tandem Mass Spectrometry with Collision-Induced Dissociation

Deamidation of Protonated Asparagine–Valine Investigated by a Combined Spectroscopic, Guided Ion Beam, and Theoretical Study

Gas-Phase Fragmentation Reactions of Protonated Cystine using High-Resolution Tandem Mass Spectrometry

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Characteristic NH₃ and CO losses from sodiated peptides C‐terminated by glutamine residues