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RESEARCH PRODUCT

ETD and ECD Mass Spectrometry Fragmentation for the Characterization of Protein Post Translational Modifications

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The introduction of electron capture dissociation (ECD) by McLafferty and co-workers, and further of electron transfer dissociation (ETD), mechanism allows gas-phase fragmentation of multiply charged protein and peptide ions upon capture of a low-energy (<1 eV) electron or electron transfer in a gas phase ion-ion chemistry. The odd-electron species then undergoes rearrangement with subsequent cleavage of N−Cα backbone. Peptide fragmentation can take place inducing the formation of cand ztype fragment ions without loss of the information on the PTM localization. The key to the success of this approach is the selection of intact protein molecular ions and its profound potential for PTM characterization as alternative to vibrational excitation techniques. With ECD, that occurs within 10-12 s, modifications that are rapidly lost upon vibrational excitation, such as phosphorylation, Nand O-glycosylation, sulfation and γ-carboxylation, can be easily established. In this Chapter, we will illustrate the ECD and ETD protein and peptides fragmentation mechanism, the MS instruments used and the parameters involved and we will provide an overview on the most recent applications of protein PTM characterization.