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Research Article
Backbone fragmentations of [M–H]– anions from peptides. Reinvestigation of the mechanism of the beta prime cleavage
Article first published online: 10 JUL 2012
DOI: 10.1002/rcm.6297
Copyright © 2012 John Wiley & Sons, Ltd.
1097-0231/asset/cover.gif?v=1&s=685086e2b20ab07e9ab5ac022b9782ebdcd7ce5c "Rapid Communications in Mass Spectrometry")
Additional Information
How to Cite
Wang, T., Tran, T. T. N., Calabrese, A. N. and Bowie, J. H. (2012), Backbone fragmentations of [M–H]– anions from peptides. Reinvestigation of the mechanism of the beta prime cleavage. Rapid Commun. Mass Spectrom., 26: 1832–1840. doi: 10.1002/rcm.6297
Publication History
- Issue published online: 2 JUL 2012
- Article first published online: 10 JUL 2012
- Manuscript Accepted: 28 MAY 2012
- Manuscript Revised: 23 MAY 2012
- Manuscript Received: 11 APR 2012
- Abstract
- Article
- References
- Cited By
RATIONALE
An experimental study has shown that the structure of a β' ion proposed earlier is incorrect. Backbone cleavage β' anions have structures R(NH–) from systems [[RNHCH(X)CONHCH(Y)CO2H (or C-terminal CONH2) – H]– (where R is the rest of the peptide molecule and X and Y represent the α side chains of the individual amino acid residues).
METHODS
Ab initio calculations were carried out at the CAM-B3LYP/6-311++g(d,p) level of theory.
CONCLUSIONS
The calculations suggest that RNH– ions are formed by SNi cyclisation processes involving either (i) the C-terminal CO2– or C-terminal [CONH]– as appropriate, or (ii) an enolate ion [-NHC–(Y)-] cyclising at the backbone CH of the -CH(X)- group. Concomitant C–N bond cleavage then liberates an RNH– ion, processes which can occur along the peptide backbone. Copyright © 2012 John Wiley & Sons, Ltd.