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

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

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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. © 2014 the Owner Societies.

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ID Code: 68901
Item Type: Journal Article
Refereed: Yes
Additional Information: Associated with grants: ARC/CE0561607, ARC/DP120102922, ARC/LE110100093
Additional URLs:
DOI: 10.1039/c3cp54825b
ISSN: 14639076
Subjects: Australian and New Zealand Standard Research Classification > CHEMICAL SCIENCE (030000)
Divisions: Current > QUT Faculties and Divisions > Science & Engineering Faculty
Copyright Owner: Royal Society of Chemistry
Deposited On: 19 Mar 2014 23:49
Last Modified: 09 Apr 2014 12:21

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