One-step peptide backbone dissociations in negative-ion free radical initiated peptide sequencing mass spectrometry

Jihye Lee, Hyeyeon Park, Hyuksu Kwon, Gyemin Kwon, Aeran Jeon, Hugh I. Kim, Bong June Sung, Bongjin Moon, Han Bin Oh

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32 Citations (Scopus)


Peptide dissociation behavior in TEMPO (2,2,6,6-tetramethylpiperidine-1- oxyl)-based FRIPS (free radical initiated peptide sequencing) mass spectrometry was analyzed in both positive-and negative-ion modes for a number of peptides including angiotensin II, kinetensin, glycoprotein IIb fragment (296-306), des-Pro2-bradykinin, and ubiquitin tryptic fragment (43-48). In the positive mode, the ·Bz-C(O)-peptide radical species was produced exclusively at the initial collisional activation of o-TEMPO-Bz-C(O)-peptides, and two consecutive applications of collisional activation were needed to observe peptide backbone fragments. In contrast, in the negative-ion mode, a single application of collisional activation to o-TEMPO-Bz-C(O)-peptides produced extensive peptide backbone fragmentations as well as ·Bz-C(O)-peptide radical species. This result indicates that the duty cycle in the TEMPO-based FRIPS mass spectrometry can be reduced by one-half in the negative-ion mode. In addition, the fragment ions observed in the negative-ion experiments were mainly of the a-, c-, x-, and z-types, indicating that radical-driven tandem mass spectrometry was mainly responsible for the TEMPO-based FRIPS even with a single application of collisional activation. Furthermore, the survival fraction analysis of o-TEMPO-Bz-C(O)-peptides was made as a function of the applied normalized collision energy (NCE). This helped us to better understand the differences in FRIPS behavior between the positive-and negative-ion modes in terms of dissociation energetics. The duty-cycle improvement made in the present study provides a cornerstone for future research aiming to achieve a single-step FRIPS in the positive-ion mode.

Original languageEnglish
Pages (from-to)7044-7051
Number of pages8
JournalAnalytical chemistry
Issue number15
Publication statusPublished - 2013 Aug 6
Externally publishedYes

ASJC Scopus subject areas

  • Analytical Chemistry


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