Bromine isotopic signature facilitates de novo sequencing of peptides in free‐radical‐initiated peptide sequencing (FRIPS) mass spectrometry
peer-reviewed · Journal of Mass Spectrometry · 2015
| Date | 2015-02-01 |
| Type | peer-reviewed |
| Venue | Journal of Mass Spectrometry |
| Publisher | Wiley |
| Contribution | adjacent |
| DOI | 10.1002/jms.3539 |
| Citations (OpenAlex) | 8 |
| Venue 2-year citedness | 1.85 |
Abstract
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.
Methods and tools
- Br-TEMPO FRIPS de novo sequencing: Adds bromine to the free-radical-initiated peptide sequencing reagent so N-terminal fragments carry a doublet signature that eases de novo reading.