Journal of the American Society for Mass Spectrometry

, Volume 17, Issue 11, pp 1605–1615

Use of a double resonance electron capture dissociation experiment to probe fragment intermediate lifetimes

Authors

  • Cheng Lin
    • Mass Spectrometry Resource, Department of BiochemistryBoston University School of Medicine
  • Jason J. Cournoyer
    • Department of ChemistryBoston University
    • Mass Spectrometry Resource, Department of BiochemistryBoston University School of Medicine
Articles

DOI: 10.1016/j.jasms.2006.07.007

Cite this article as:
Lin, C., Cournoyer, J.J. & O’Connor, P.B. J Am Soc Mass Spectrom (2006) 17: 1605. doi:10.1016/j.jasms.2006.07.007

Abstract

The relative abundances of fragment ions in electron capture dissociation (ECD) are often greatly affected by the secondary and tertiary structures of the precursor ion, and have been used to derive the gas-phase conformations of the protein ions. In this study, it is found that resonance ejection of the charge reduced molecular ion during ECD resulted in significant changes in many fragment ion populations. The ratio of the ion peak intensities in the double resonance (DR)-ECD to that in the normal ECD experiment can be used to calculate the lifetime of the radical intermediates from which these fragments are derived. These lifetimes are often in the ms range, a time sufficiently long to facilitate multiple free radical rearrangements. These ratios correlate with the intramolecular noncovalent interactions in the precursor ion, and can be used to deduce information about the gas-phase conformation of peptide ions. DR-ECD experiments can also provide valuable information on ECD mechanisms, such as the importance of secondary electron capture and the origin of c·/z ions.

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© American Society for Mass Spectrometry 2006