Models of Fragmentations Induced by Electron Attachment to Protonated Peptides
- 1 October 2004
- journal article
- Published by SAGE Publications in European Journal of Mass Spectrometry
- Vol. 10 (5) , 625-638
- https://doi.org/10.1255/ejms.665
Abstract
Invoking a number of theoretical levels ranging from HF/STO-3G to CCSD(T)/aug-cc-pVQZ, we have made a detailed survey of six potential energy surfaces (NH4+, NH4•, [CH3CONHCH3]H+, [CH3CONHCH3]H•, [HCONHCH2CONH2]H+ and [HCONHCH2CONH2]H•). In conjunction with this, ab inito direct dynamics calculations have been conducted, tracing out several hundred reaction trajectories to reveal details of the electron-capture dissociation mechanism. The model calculations suggest the possibility of a bimodal pattern where some of the radicals, formed upon recombination, dissociate almost directly within one picosecond, the remaining radicals being subject to complete energy redistribution with a subsequent dissociation occurring at the microsecond timescale. Both processes give rise to c and z backbone fragments, resulting from cleavage of N?Cα bonds of the peptide chain.Keywords
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