Supplemental Activation Method for High-Efficiency Electron-Transfer Dissociation of Doubly Protonated Peptide Precursors

Citations Over TimeTop 1% of 2006 papers

Abstract

Electron-transfer dissociation (ETD) delivers the unique attributes of electron capture dissociation to mass spectrometers that utilize radio frequency trapping-type devices (e.g., quadrupole ion traps). The method has generated significant interest because of its compatibility with chromatography and its ability to: (1) preserve traditionally labile post-translational modifications (PTMs) and (2) randomly cleave the backbone bonds of highly charged peptide and protein precursor ions. ETD, however, has shown limited applicability to doubly protonated peptide precursors, [M + 2H]2+, the charge and type of peptide most frequently encountered in "bottom-up" proteomics. Here we describe a supplemental collisional activation (CAD) method that targets the nondissociated (intact) electron-transfer (ET) product species ([M + 2H]+*) to improve ETD efficiency for doubly protonated peptides (ETcaD). A systematic study of supplementary activation conditions revealed that low-energy CAD of the ET product population leads to the near-exclusive generation of c- and z-type fragment ions with relatively high efficiency (77 +/- 8%). Compared to those formed directly via ETD, the fragment ions were found to comprise increased relative amounts of the odd-electron c-type ions (c+*) and the even-electron z-type ions (z+). A large-scale analysis of 755 doubly charged tryptic peptides was conducted to compare the method (ETcaD) to ion trap CAD and ETD. ETcaD produced a median sequence coverage of 89%-a significant improvement over ETD (63%) and ion trap CAD (77%).

Related Papers

• → Characterizing protein glycosylation sites through higher‐energy C‐trap dissociation(2010)121 cited
• → Analysis of proteins and peptides on a chromatographic timescale by electron‐transfer dissociation MS(2007)40 cited
• → Transmission Mode Ion/Ion Electron-Transfer Dissociation in a Linear Ion Trap(2007)34 cited
• → Mass Selective Ion Transfer and Accumulation in Ion Trap Arrays(2014)26 cited
• → Beam‐type collisional activation of polypeptide cations that survive ion/ion electron transfer(2007)21 cited