Gas-Phase Fragmentation of [M + nH + OH]<sup>n•+</sup> Ions Formed from Peptides Containing Intra-Molecular Disulfide Bonds

Ma, Xiaoxiao; Love, Chasity B.; Zhang, Xinrong; Xia, Yu

doi:10.1007/s13361-011-0104-1

Cited by 17 publications

(19 citation statements)

References 49 publications

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“…Data shown here were typical an average of more than 50 scans. In order to conduct AP ion/radical reactions, the nanoESI plume of peptide sample was allowed to interact with the after-glow region of an AP helium low temperature plasma (LTP) enabled in the side arm of a T-shaped glass tube placed in front of the entrance of mass spectrometer [58]. The schematics of the instrument and reaction setup are shown in Scheme S-1 of the supplemental material.…”

Section: Mass Spectrometry and Ap Radical Reactionsmentioning

confidence: 99%

“…For peptides having intra-chain disulfide bonds, one major product after the nanoESI plume interacting with LTP were ions corresponding to the addition of O and H to the intact peptide ([M + nH + OH] n•+ ) [58,59]. Note that since many oxidative radicals or species coexisted in the helium LTP, the exact reaction mechanism for this phenomenon was unclear.…”

Section: Formation Of Peptide Sulfinyl Radical Ions Radical Attack Ofmentioning

confidence: 99%

“…Given the coexistence of radical and charge, the competition of charge-versus radical-directed fragmentation pathways is of special interest. The ion trap CID spectra of four singly protonated peptide sulfinyl radical ions are selected to represent the general fragmentation behavior (Figure 4) ions derived from intra-chain disulfide peptides [58]. The 62 Da loss was proposed to be radical driven, resulting from a homolytic cleavage between the α-and β-carbons on the sulfinyl radical side chain as shown in Scheme 2.…”

Section: Unimolecular Dissociation Of Peptide Sulfinyl Radical Cationsmentioning

confidence: 99%

“…Due to the transient nature of radical species in solution, very little has been explored on the chemical property of protein or peptide sulfinyl radicals. In previous studies, we observed that disulfide bonds within peptides could be cleaved when the peptide nanoelectrospray plume was allowed to interact with the after-glow of a helium plasma in air, resulting in the formation of sulfinyl radical (−SO•) and sulfhydryl (−SH) at the cleavage site [58,59]. Atmospheric pressure (AP) reactions induced by reactive radicals were suggested to be responsible for the oxidative cleavage of the disulfide bond.…”

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confidence: 99%

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Gas-Phase Peptide Sulfinyl Radical Ions: Formation and Unimolecular Dissociation

Tan

Xia

2012

J. Am. Soc. Mass Spectrom.

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A variety of peptide sulfinyl radical (RSO•) ions with a well-defined radical site at the cysteine side chain were formed at atmospheric pressure (AP), sampled into a mass spectrometer, and investigated via collision-induced dissociation (CID). The radical ion formation was based on AP reactions between oxidative radicals and peptide ions containing single inter-chain disulfide bond or free thiol group generated from nanoelectrospray ionization (nanoESI). The radical induced reactions allowed large flexibility in forming peptide radical ions independent of ion polarity (protonated or deprotonated) or charge state (singly or multiply charged). More than 20 peptide sulfinyl radical ions in either positive or negative ion mode were subjected to low energy collisional activation on a triple-quadrupole/linear ion trap mass spectrometer. The competition between radical-and charge-directed fragmentation pathways was largely affected by the presence of mobile protons. For peptide sulfinyl radical ions with reduced proton mobility (i.e., singly protonated, containing basic amino acid residues), loss of 62 Da (CH 2 SO), a radicalinitiated dissociation channel, was dominant. For systems with mobile protons, this channel was suppressed, while charge-directed amide bond cleavages were preferred. The polarity of charge was found to significantly alter the radical-initiated dissociation channels, which might be related to the difference in stability of the product ions in different ion charge polarities.

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Section: Mass Spectrometry and Ap Radical Reactionsmentioning

confidence: 99%

Section: Formation Of Peptide Sulfinyl Radical Ions Radical Attack Ofmentioning

confidence: 99%

Section: Unimolecular Dissociation Of Peptide Sulfinyl Radical Cationsmentioning

confidence: 99%

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confidence: 99%

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Gas-Phase Peptide Sulfinyl Radical Ions: Formation and Unimolecular Dissociation

Tan

Xia

2012

J. Am. Soc. Mass Spectrom.

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“…The experimental setup has been described in detail before [32]. Briefly, peptide solutions for nanoelectrospray ionization (nanoESI) [33] were prepared at a concentration of 10 mM in 50/49/1.0 of water/methanol/acetic acid (v/v/v).…”

Section: Radical Reactions In Nanoesi Plume and Mass Spectrometrymentioning

confidence: 99%

Intra-molecular reactions between cysteine sulfinyl radical and a disulfide bond within peptide ions

Durand

Xia

2015

International Journal of Mass Spectrometry

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Tautomerization and Dissociation of Molecular Peptide Radical Cations

Mu¹,

Song²,

Siu

et al. 2017

The Chemical Record

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Radical-mediated dissociations of peptide radical cations have intriguing unimolecular gas phase chemistry, with cleavages of almost every bond of the peptide backbone and amino acid side chains in a competitive and apparently "stochastic" manner. Challenges of unraveling mechanistic details are related to complex tautomerizations prior to dissociations. Recent conjunctions of experimental and theoretical investigations have revealed the existence of non-interconvertible isobaric tautomers with a variety of radical-site-specific initial structures, generated from dissociative electron transfer of ternary metal-ligand-peptide complexes. Their reactivity is influenced by the tautomerization barriers, perturbing the nature, location, or number of radical and charge site(s), which also determine the energetics and dynamics of the subsequent radical-mediated dissociatons. The competitive radical- and charge-induced dissociations are extremely dependent on charge density. Charge sequesting can reduce the charge densities on the peptide backbone and hence enhance the flexibility of structural rearrangement. Analysing the structures of precursors, intermediates and products has led to the discovery of many novel radical migration prior to peptide backbone and/or side chain fragmentations. Upon these successes, scientists will be able to build peptide cationic analogues/tautomers having a variety of well-defined radical sites.

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Gas-Phase Fragmentation of [M + nH + OH]^n•+ Ions Formed from Peptides Containing Intra-Molecular Disulfide Bonds

Cited by 17 publications

References 49 publications

Gas-Phase Peptide Sulfinyl Radical Ions: Formation and Unimolecular Dissociation

Gas-Phase Peptide Sulfinyl Radical Ions: Formation and Unimolecular Dissociation

Intra-molecular reactions between cysteine sulfinyl radical and a disulfide bond within peptide ions

Tautomerization and Dissociation of Molecular Peptide Radical Cations

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Gas-Phase Fragmentation of [M + nH + OH]n•+ Ions Formed from Peptides Containing Intra-Molecular Disulfide Bonds

Cited by 17 publications

References 49 publications

Gas-Phase Peptide Sulfinyl Radical Ions: Formation and Unimolecular Dissociation

Gas-Phase Peptide Sulfinyl Radical Ions: Formation and Unimolecular Dissociation

Intra-molecular reactions between cysteine sulfinyl radical and a disulfide bond within peptide ions

Tautomerization and Dissociation of Molecular Peptide Radical Cations

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Product

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Gas-Phase Fragmentation of [M + nH + OH]^n•+ Ions Formed from Peptides Containing Intra-Molecular Disulfide Bonds