Bromine isotopic signature facilitates de novo sequencing of peptides in free‐radical‐initiated peptide sequencing (FRIPS) mass spectrometry. (3rd February 2015)

• Record Type: Journal Article
• Authors: Nam, Jungjoo; Kwon, Hyuksu; Jang, Inae; Jeon, Aeran; Moon, Jingyu; Lee, Sun Young; Kang, Dukjin; Han, Sang Yun; Moon, Bongjin; Oh, Han Bin
• Is Part Of: Journal of mass spectrometry. Volume 50:Number 2(2015:Feb.)
• Page Start: 378
• Page End: 387
• Publication Date: 2015-02-03
• Subjects: free‐radical‐initiated peptide sequencing (FRIPS) -- bromine signature -- isotopic pattern -- de novo sequencing -- radical‐based tandem mass spectrometry; Mass spectrometry -- Periodicals; 543.65
• DOI: 10.1002/jms.3539
• Languages: English
• ISSNs: 1076-5174

Abstract

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. Copyright © 2015 John Wiley & Sons, Ltd.