Electron Transfer Dissociation

Electron transfer dissociation is a popular peptide fragmentation technique in mass spectrometry. It requires multiply-charged gas-phase cations (z>2) and therefore it is typically limited to an electron spray ion source.

The sample, usually in solution, is first ionized by electrospray, and gas-phase "precursor" ions are then captured in an ion trap. ETD fragmentation proceeds in two steps. First, the precursor cation, usually a protein or peptide carrying multiple positive charges, reacts with a pre-ionized anion (e.g., fluoranthene). Capture of an electron from the anion yields an unstable cation radical (Figure 1).

Protein/peptide precursor multiply-charged cation reacts with an anion to form a radical cation.Figure 1. Protein/peptide precursor multiply-charged cation reacts with an anion to form a radical cation.

Second, the cation radical then breaks into two fragments, usually one c ion and one z ion (Figure 2). The cleavage is between α-carbon and nitrogen as shown in Figure 3.

Protein/peptide radical cation fragmentation into a c ion and a z ion.Figure 2. Protein/peptide radical cation fragmentation into a c ion and a z ion.

 

Bond cleavage in ETD and chemical structures of the c and z ions.Figure 3. Bond cleavage in ETD and chemical structures of the c and z ions.

The cleavages occur randomly on the protein backbone between any two amino acids (except proline), whereas the side chains can read out a protein amino acid sequence without losing any side chain or chemical modification information.

This technique can be used with the following instruments:

Related Publications

Y. Mao, et al, Top-Down Structural Analysis of an Intact Monoclonal Antibody by Electron Capture Dissociation-Fourier Transform Ion Cyclotron Resonance-Mass Spectrometry, Analytical Chemistry 85(9), 4239-4246 (2013) Read online 


Y. Mao, et al, Valence Parity to Distinguish c′ and z• Ions from Electron Capture Dissociation/Electron Transfer Dissociation of Peptides: Effects of Isomers, Isobars, and Proteolysis Specificity, Analytical Chemistry 83(20), 8024-8028 (2011) Read online 


H. Ben, et al, Periodic Sequence Distribution of Product Ion Abundances in Electron Capture Dissociation of Amphipathic Peptides and Proteins, Journal of the American Society for Mass Spectrometry 20(6), 1182-1192 (2009) Read online 


Y. Tsybin, et al, Electron Capture Dissociation Implementation Progress in Fourier Transform Ion Cyclotron Resonance Mass Spectrometry, Journal of the American Society for Mass Spectrometry 19(6), 762-771 (2008) Read online 


Y. Tsybin, et al, Ion Activation in Electron Capture Dissociation To Distinguish between N-Terminal and C-Terminal Product Ions, Analytical Chemistry 79(20), 7596–7602 (2007) Read online 


Y. Tsybin, et al, Charge Location Directs Electron Capture Dissociation of Peptide Dications, Journal of the American Society for Mass Spectrometry 17(12), 1704-1711 (2006) Read online 


For more information please contact Amy McKenna, Manager, ICR User Program.

Last modified on 28 August 2015