Activated Ion Electron Transfer Dissociation for Improved Fragmentation of Intact Proteins

Anal Chem. 2015 Jul 21;87(14):7109-16. doi: 10.1021/acs.analchem.5b00881. Epub 2015 Jun 26.

Abstract

Here we report the first implementation of activated ion electron transfer dissociation (AI-ETD) for top down protein characterization, showing that AI-ETD definitively extends the m/z range over which ETD can be effective for fragmentation of intact proteins. AI-ETD, which leverages infrared photon bombardment concurrent to the ETD reaction to mitigate nondissociative electron transfer, was performed using a novel multipurpose dissociation cell that can perform both beam-type collisional dissociation and ion-ion reactions on an ion trap-Orbitrap hybrid mass spectrometer. AI-ETD increased the number of c- and z-type product ions for all charge states over ETD alone, boosting product ion yield by nearly 4-fold for low charge density precursors. AI-ETD also outperformed HCD, generating more matching fragments for all proteins at all charge states investigated. In addition to generating more unique fragment ions, AI-ETD provided greater protein sequence coverage compared to both HCD and ETD. In all, the effectiveness of AI-ETD across the entirety of the m/z spectrum demonstrates its efficacy for robust fragmentation of intact proteins.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Electron Transport
  • Electrons
  • Ions / chemistry
  • Peptides / analysis*
  • Peptides / chemistry
  • Proteins / chemistry*
  • Proteins / metabolism
  • Spectrometry, Mass, Electrospray Ionization*

Substances

  • Ions
  • Peptides
  • Proteins