Rapid, quantitative, and site specific synthesis of biomolecular radicals from a simple photocaged precursor

Ly, Tony; Zhang, Xing; Sun, Qingyu; Moore, Benjamin; Tao, Yuanqi; Julian, Ryan R.

doi:10.1039/c0cc03363d

Cited by 36 publications

(47 citation statements)

References 25 publications

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“…In studies where site specific radicals are generated by laser photolysis of iodinated ion precursors, [38][39][40]43,[57][58][59] this band is very well-matched to the 4 th harmonic (266 nm) of the commercially available Nd:YAG laser.…”

Section: Resultsmentioning

confidence: 99%

UV Photodissociation Action Spectroscopy of Haloanilinium Ions in a Linear Quadrupole Ion Trap Mass Spectrometer

Hansen

Kirk

Blanksby

et al. 2013

J. Am. Soc. Mass Spectrom.

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. (2013). UV photodissociation action spectroscopy of haloanilinium ions in a linear quadrupole ion trap mass spectrometer. Journal of the American Society for Mass Spectrometry, 24 (6), 932-940. UV photodissociation action spectroscopy of haloanilinium ions in a linear quadrupole ion trap mass spectrometer Abstract UV-vis photodissociation action spectroscopy is becoming increasingly prevalent because of advances in, and commercial availability of, ion trapping technologies and tunable laser sources. This study outlines in detail an instrumental arrangement, combining a commercial ion-trap mass spectrometer and tunable nanosecond pulsed laser source, for performing fully automated photodissociation action spectroscopy on gas-phase ions. The components of the instrumentation are outlined, including the optical and electronic interfacing, in addition to the control software for automating the experiment and performing online analysis of the spectra. To demonstrate the utility of this ensemble, the photodissociation action spectra of 4-chloroanilinium, 4-bromoanilinium, and 4-iodoanilinium cations are presented and discussed. Multiple photoproducts are detected in each case and the photoproduct yields are followed as a function of laser wavelength. It is shown that the wavelength-dependent partitioning of the halide loss, H loss, and NH3 loss channels can be broadly rationalized in terms of the relative carbon-halide bond dissociation energies and processes of energy redistribution. The photodissociation action spectrum of (phenyl)Ag2 + is compared with a literature spectrum as a further benchmark. AbstractUV-Vis photodissociation action spectroscopy is becoming increasingly prevalent due to advances in, and commercial availability of, ion trapping technologies and tunable laser sources. This study outlines in detail an instrumental arrangement, combining a commercial ion-trap mass spectrometer and tunable nanosecond pulsed laser source, for performing fully automated photodissociation action spectroscopy on gas-phase ions. The components of the instrumentation are outlined, including the optical and electronic interfacing, in addition to the control software for automating the experiment and performing online analysis of the spectra. To demonstrate the utility of this ensemble, the photodissociation action spectra of 4-chloroanilinium, 4-bromoanilinium and 4-iodoanilinium cations are presented and discussed. Multiple photoproducts are detected in each case and the photoproduct yields are followed as a function of laser wavelength. It is shown that the wavelength-dependent partitioning of the halide loss, H loss and NH 3 loss channels can be broadly rationalized in terms of the relative carbon-halide bond dissociation energies and processes of energy redistribution. The photodissociation action spectrum of (phenyl)Ag 2 + is compared to a literature spectrum as a further benchmark.3

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Section: Resultsmentioning

confidence: 99%

UV Photodissociation Action Spectroscopy of Haloanilinium Ions in a Linear Quadrupole Ion Trap Mass Spectrometer

Hansen

Kirk

Blanksby

et al. 2013

J. Am. Soc. Mass Spectrom.

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“…39,40 Strategies that utilise UV radiation and a photolabile radical precursor show promise for peptide characterisation. High photoproduct yields, 41 the availability of tuneable laser sources, and avoiding the low-mass cut-off inherent in ion trap-based analysis 42 offer an opportunity for enhanced peptide sequencing coverage over collisional and electron-based tandem mass spectrometric methods.…”

Section: Introductionmentioning

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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“…23 N-hydroxysuccinimide (NHS) activated iodobenzoyl esters were synthesized by following a previous procedure. 16 Chloramine-T, sodium metabisulfite, and sodium iodide were purchased from Fisher Chemical (Fairlawn, NJ). Water was purified to 18.2 MΩ resistivity using a Millipore Direct-Q (Millipore, Billerica, MA.…”

Section: Methodsmentioning

confidence: 99%

“…14 Many bonds have been demonstrated to be suitable, including carbon-iodine, carbon-sulfur, and sulfur-sulfur. 15 In optimal cases, radical yields can be quantitative with a single laser pulse, 16 but implementation requires coupling an ultraviolet laser to a mass spectrometer—an experimental configuration that is not currently commercially available. The need for customized instrumentation has likely limited accessibility to the technique.…”

Section: Introductionmentioning

confidence: 99%

Leveraging Electron Transfer Dissociation for Site Selective Radical Generation: Applications for Peptide Epimer Analysis

Lyon

Beran

Julian

2017

J. Am. Soc. Mass Spectrom.

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Traditional electron-transfer dissociation (ETD) experiments operate through a complex combination of hydrogen abundant and hydrogen deficient fragmentation pathways, yielding c and z ions, side chains losses, and disulfide bond scission. Herein, a novel dissociation pathway is reported, yielding homolytic cleavage of carbon-iodine bonds via electronic excitation. This observation is very similar to photodissociation experiments where homolytic cleavage of carbon-iodine bonds has been utilized previously, but ETD-activation can be performed without addition of a laser to the mass spectrometer. Both loss of iodine and loss of hydrogen iodide are observed, with the abundance of the latter product being greatly enhanced for some peptides after additional collisional activation. These observations suggest a novel ETD fragmentation pathway involving temporary storage of the electron in a charge-reduced arginine side chain. Subsequent collisional activation of the peptide radical produced by loss of HI yields spectra dominated by radical-directed dissociation, which can be usefully employed for identification of peptide isomers, including epimers.

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Rapid, quantitative, and site specific synthesis of biomolecular radicals from a simple photocaged precursor

Cited by 36 publications

References 25 publications

UV Photodissociation Action Spectroscopy of Haloanilinium Ions in a Linear Quadrupole Ion Trap Mass Spectrometer

UV Photodissociation Action Spectroscopy of Haloanilinium Ions in a Linear Quadrupole Ion Trap Mass Spectrometer

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

Leveraging Electron Transfer Dissociation for Site Selective Radical Generation: Applications for Peptide Epimer Analysis

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