Journal of the American Society for Mass Spectrometry

, Volume 21, Issue 8, pp 1455–1465

Gas-phase conformation-specific photofragmentation of proline-containing peptide ions


  • Tae-Young Kim
    • Department of ChemistryIndiana University
  • Stephen J. Valentine
    • Department of ChemistryIndiana University
  • David E. Clemmer
    • Department of ChemistryIndiana University
    • Department of ChemistryIndiana University

DOI: 10.1016/j.jasms.2010.04.007

Cite this article as:
Kim, T., Valentine, S.J., Clemmer, D.E. et al. J Am Soc Mass Spectrom (2010) 21: 1455. doi:10.1016/j.jasms.2010.04.007


Singly-protonated proline-containing peptides with N-terminal arginine are photodissociated with vacuum ultraviolet (VUV) light in an ESI linear ion trap/orthogonal-TOF (LIT/o-TOF). When proline is the nth residue from the N-terminus, unusual bn + 2 and an + 2 ions are observed. Their formation is explained by homolytic cleavage of the Cα− C bond in conjunction with a rearrangement of electrons and an amide hydrogen. The latter is facilitated by a proline-stabilized gas-phase peptide conformation.

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© American Society for Mass Spectrometry 2010