Electron capture and deprotonation processes observed in collisions between Xe8+ and multiply protonated cytochrome-C

S. Martin*, C. Ortega, L. Chen, R. Bredy, A. Vernier, P. Dugourd, R. Antoine, J. Bernard, G. Reitsma, Olmo Gonzalez Magana, Ronnie Hoekstra, Thomas Schlathölter

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

10 Citations (Scopus)

Abstract

Electron-transfer processes in interaction between highly charged ions and multiply protonated proteins have been studied. Collisions between Xe8+ at 96 keV and protonated cytochrome-C at selected charge state (q from 15+ to 19+) result inmass spectra composed mainly of intact molecular ions. From the spectra, single and double electron capture processes by Xe8+ from the protonated molecular ions were identified and the relative cross sections were measured. An unexpected process, the deprotonation process, was also observed. It is tentatively attributed to the loss of a proton induced by the strong electric field carried by the projectile ion in long-distance collisions. Upon charge variation of the molecular target from 15 to 19, the single and double electron capture cross sections remain nearly constant, while the relative cross section of the deprotonation process increases dramatically from 0.8% (+/- 0.1%) to 17% (+/- 1%). This strong charge dependency is explained by the decrease of the proton affinities with the charge. This proton removal process has not been observed previously. It seems to be specific to the long-distance Coulomb interactions between protons bound along the protein chain and the highly charged atomic ions.

Original languageEnglish
Article number012707
Number of pages8
JournalPhysical Review A
Volume89
Issue number1
DOIs
Publication statusPublished - 13-Jan-2014

Keywords

  • HIGHLY CHARGED IONS
  • GAS-PHASE
  • TRANSFER DISSOCIATION
  • MASS-SPECTROMETRY
  • ANIONS
  • FRAGMENTATION
  • IONIZATION
  • PROTEOMICS
  • ENERGIES
  • TRAP

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