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

Journal Article


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Abstract


  • Radical-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 radical-directed dissociation.

Authors


  •   Marshall, David L. (external author)
  •   Hansen, Christopher (external author)
  •   Trevitt, Adam J.
  •   Oh, Han Bin. (external author)
  •   Blanksby, Stephen J. (external author)

Publication Date


  • 2014

Citation


  • Marshall, D. L., Hansen, C., Trevitt, A. J., Oh, H. Bin. & Blanksby, S. J. (2014). Photodissociation of TEMPO-modified peptides: new approaches to radical-directed dissociation of biomolecules. Physical Chemistry Chemical Physics, 16 (10), 4871-4879.

Scopus Eid


  • 2-s2.0-84894136572

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=2477&context=smhpapers

Ro Metadata Url


  • http://ro.uow.edu.au/smhpapers/1459

Has Global Citation Frequency


Number Of Pages


  • 8

Start Page


  • 4871

End Page


  • 4879

Volume


  • 16

Issue


  • 10

Place Of Publication


  • United Kingdom

Abstract


  • Radical-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 radical-directed dissociation.

Authors


  •   Marshall, David L. (external author)
  •   Hansen, Christopher (external author)
  •   Trevitt, Adam J.
  •   Oh, Han Bin. (external author)
  •   Blanksby, Stephen J. (external author)

Publication Date


  • 2014

Citation


  • Marshall, D. L., Hansen, C., Trevitt, A. J., Oh, H. Bin. & Blanksby, S. J. (2014). Photodissociation of TEMPO-modified peptides: new approaches to radical-directed dissociation of biomolecules. Physical Chemistry Chemical Physics, 16 (10), 4871-4879.

Scopus Eid


  • 2-s2.0-84894136572

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=2477&context=smhpapers

Ro Metadata Url


  • http://ro.uow.edu.au/smhpapers/1459

Has Global Citation Frequency


Number Of Pages


  • 8

Start Page


  • 4871

End Page


  • 4879

Volume


  • 16

Issue


  • 10

Place Of Publication


  • United Kingdom