Charge-Directed Peptide Backbone Dissociations of o-TEMPO-Bz-C(O)-Peptides

Jeon, Aeran; Lee, Ji Hye; Kwon, Hyuk Su; Park, Hyung Soon; Moon, Bongjin; Oh, Han Bin

doi:10.5478/msl.2013.4.4.71

Cited by 15 publications

(34 citation statements)

References 31 publications

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“…Although this method is somewhat analogous to ECD and ETD, it does not require multiple charges for fragmentation to occur. In fact, the presence of more charges than the number of basic groups can actually inhibit the radical pathways and facilitate charge-induced fragmentation [46]. …”

Section: Introductionmentioning

confidence: 99%

Distinguishing Aspartic and Isoaspartic Acids in Peptides by Several Mass Spectrometric Fragmentation Methods

DeGraan-Weber

Zhang

Reilly

2016

J. Am. Soc. Mass Spectrom.

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Six ion fragmentation techniques that can distinguish aspartic acid from its isomer, isoaspartic acid, were compared. MALDI post source decay (PSD), MALDI 157 nm photodissociation, TMPP charge tagging in PSD and photodissociation, ESI collision-induced dissociation (CID), electron transfer dissociation (ETD), and free-radical initiated peptide sequencing (FRIPS) with CID were applied to peptides containing either aspartic or isoaspartic acid. Diagnostic ions, such as the y-46 and b+H2O, are present in PSD, photodissociation, and charge tagging. c•+57 and z-57 ions are observed in ETD and FRIPS experiments. For some molecules, aspartic and isoaspartic acid yield ion fragments with significantly different intensities. ETD and charge tagging appear to be most effective at distinguishing these residues.

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Section: Introductionmentioning

confidence: 99%

Distinguishing Aspartic and Isoaspartic Acids in Peptides by Several Mass Spectrometric Fragmentation Methods

DeGraan-Weber

Zhang

Reilly

2016

J. Am. Soc. Mass Spectrom.

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“…Similar observations were made for other peptides when the number of charges approached or exceeded the number of basic side chains available, placing an upper limit on the charge states for which CID and PD 266 can produce the desired radical ions. 53 Advantageously, the TEMPO-based FRIPS methodology is also applicable to the study of negative ions. 29 Negative ion mass spectrometry provides structural information for proteomics that is both confirmatory and complementary to that obtained in the study of positive ions.…”

Section: Mass Spectrometrymentioning

confidence: 99%

Photodissociation of TEMPO-modified peptides: new approaches to radical-directed dissociation of biomolecules

Marshall

Hansen

Trevitt

et al. 2014

Phys. Chem. Chem. Phys.

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Photodissociation of TEMPO-modified peptides: new approaches to radical-directed dissociation of biomolecules AbstractRadical-directed dissociation of gas phase ions is emerging as a powerful and complementary alternative to traditional tandem mass spectrometric techniques for biomolecular structural analysis. Previous studies have identified that coupling of 2-[(2,2,6,6-tetramethylpiperidin-1-oxyl)methyl]benzoic acid (TEMPO-Bz) to the N-terminus of a peptide introduces a labile oxygen-carbon bond that can be selectively activated upon collisional activation to produce a radical ion. Here we demonstrate that structurally-defined peptide radical ions can also be generated upon UV laser photodissociation of the same TEMPO-Bz derivatives in a linear ion-trap mass spectrometer. When subjected to further mass spectrometric analyses, the radical ions formed by a single laser pulse undergo identical dissociations as those formed by collisional activation of the same precursor ion, and can thus be used to derive molecular structure. Mapping the initial radical formation process as a function of photon energy by photodissociation action spectroscopy reveals that photoproduct formation is selective but occurs only in modest yield across the wavelength range (300-220 nm), with the photoproduct yield maximised between 235 and 225 nm. Based on the analysis of a set of model compounds, structural modifications to the TEMPO-Bz derivative are suggested to optimise radical photoproduct yield. Future development of such probes offers the advantage of increased sensitivity and selectivity for radicaldirected dissociation. AbstractRadical-directed dissociation of gas phase ions is emerging as a powerful and complementary alternative to traditional tandem mass spectrometric techniques for biomolecular structural analysis. Previous studies have identified that coupling of 2-[(2,2,6,6-tetramethylpiperidin-1-oxyl)methyl]benzoic acid (TEMPO-Bz) to the N-terminus of a peptide introduces a labile oxygen-carbon bond that can be selectively activated upon collisional activation to produce a radical ion. Here we demonstrate that structurally-defined peptide radical ions can also be generated upon UV laser photodissociation of the same TEMPO-Bz derivatives in a linear ion-trap mass spectrometer. When subjected to further mass spectrometric analyses, the radical ions formed by a single laser pulse undergo identical dissociations as those formed by collisional activation of the same precursor ion, and can thus be used to derive molecular structure. Mapping the initial radical formation process as a function of photon energy by photodissociation action spectroscopy reveals that photoproduct formation is selective but occurs only in modest yield across the wavelength range (300 -220 nm), with the photoproduct yield maximised between 235 and 225 nm. Based on the analysis of a set of model compounds, structural modifications to the TEMPO-Bz derivative are suggested to optimise radical photoproduct yield. Future development of such probes offers t...

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“…Figure (b) was obtained by providing the normalized collision energy of 15.0 onto singly protonated o ‐TEMPO–Bz(Br)–C(O)–kinetensin, ( R M + H) + . As in the previous FRIPS MS experiments, o ‐TEMPO–Bz(Br)–C(O)–kinetensin ions underwent homolytic dissociation predominantly at the bond between the oxygen of the TEMPO group and the benzylic carbon, producing radical fragment •Bz(Br)–C(O)–kinetensin, ( r M + H) +• , at m/z = 1366.6 . The gas‐phase free energy of the C–O bond homolysis, which generates TEMPO and benzyl radicals, was theoretically predicted to be low at the level of G3(MP2)‐RAD//B3LYP/6‐31G(d), i.e.…”

Section: Resultsmentioning

confidence: 64%

“…electron capture dissociation and ETD, have shown that the radical sites generated through the combination of protonated sites and electrons can induce extensive peptide/protein backbone dissociations . The recognition of the important role played by the radical site in peptide sequencing has triggered the development of a variety of radical‐based MS methods . Collisional activation of ternary metal–peptide–ligand complexes yields peptide radical cations .…”

Section: Introductionmentioning

confidence: 99%

“…Upon subsequent activation, a / x ‐type or c / z ‐type peptide backbone dissociations occur as major fragmentation pathways; this is the so‐called free‐radical‐initiated peptide sequencing (FRIPS) approach. Representative free‐radical initiators include peroxycarbamates, azo moieties, N ‐nitroso or S ‐nitroso derivatives in tryptophan and cysteine‐containing peptides, and [(TEMPO)methyl]benzoic acid (TEMPO–Bz) group . We employ the o ‐TEMPO–Bz– group as a radical‐initiating motif at the location of the N‐terminus in the present study.…”

Section: Introductionmentioning

confidence: 99%

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Bromine isotopic signature facilitates de novo sequencing of peptides in free‐radical‐initiated peptide sequencing (FRIPS) mass spectrometry

et al. 2015

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We recently showed that free-radical-initiated peptide sequencing mass spectrometry (FRIPS MS) assisted by the remarkable thermochemical stability of (2,2,6,6-tetramethyl-piperidin-1-yl)oxyl (TEMPO) is another attractive radical-driven peptide fragmentation MS tool. Facile homolytic cleavage of the bond between the benzylic carbon and the oxygen of the TEMPO moiety in o-TEMPO-Bz-C(O)-peptide and the high reactivity of the benzylic radical species generated in •Bz-C(O)-peptide are key elements leading to extensive radical-driven peptide backbone fragmentation. In the present study, we demonstrate that the incorporation of bromine into the benzene ring, i.e. o-TEMPO-Bz(Br)-C(O)-peptide, allows unambiguous distinction of the N-terminal peptide fragments from the C-terminal fragments through the unique bromine doublet isotopic signature. Furthermore, bromine substitution does not alter the overall radical-driven peptide backbone dissociation pathways of o-TEMPO-Bz-C(O)-peptide. From a practical perspective, the presence of the bromine isotopic signature in the N-terminal peptide fragments in TEMPO-assisted FRIPS MS represents a useful and cost-effective opportunity for de novo peptide sequencing.

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Charge-Directed Peptide Backbone Dissociations of o-TEMPO-Bz-C(O)-Peptides

Cited by 15 publications

References 31 publications

Distinguishing Aspartic and Isoaspartic Acids in Peptides by Several Mass Spectrometric Fragmentation Methods

Distinguishing Aspartic and Isoaspartic Acids in Peptides by Several Mass Spectrometric Fragmentation Methods

Photodissociation of TEMPO-modified peptides: new approaches to radical-directed dissociation of biomolecules

Bromine isotopic signature facilitates de novo sequencing of peptides in free‐radical‐initiated peptide sequencing (FRIPS) mass spectrometry

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