Neil L. Kelleher

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTElectron Capture Dissociation of Multiply Charged Protein Cations. A Nonergodic ProcessRoman A. Zubarev, Neil L. Kelleher, and Fred W. McLaffertyView Author Information Department of Chemistry, Baker Laboratory Cornell University, Ithaca, New York 14853-1301 Cite this: J. Am. Chem. Soc. 1998, 120, 13, 3265–3266Publication Date (Web):March 24, 1998Publication History Received6 October 1997Published online24 March 1998Published inissue 1 April 1998https://doi.org/10.1021/ja973478kCopyright © 1998 American Chemical SocietyRequest reuse permissionsArticle Views5758Altmetric-Citations1640LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit Read OnlinePDF (80 KB) Get e-AlertscloseSUBJECTS:Circular dichroism spectroscopy,Crystal cleavage,Dissociation,Ions,Peptides and proteins Get e-Alerts

For proteins of < 20 kDa, this new radical site dissociation method cleaves different and many more backbone bonds than the conventional MS/MS methods (e.g., collisionally activated dissociation, CAD) that add energy directly to the even-electron ions. A minimum kinetic energy difference between the electron and ion maximizes capture; a 1 eV difference reduces capture by 10(3). Thus, in an FTMS ion cell with added electron trapping electrodes, capture appears to be achieved best at the boundary between the potential wells that trap the electrons and ions, now providing 80 +/- 15% precursor ion conversion efficiency. Capture cross section is dependent on the ionic charge squared (z2), minimizing the secondary dissociation of lower charge fragment ions. Electron capture is postulated to occur initially at a protonated site to release an energetic (approximately 6 eV) H. atom that is captured at a high-affinity site such as -S-S- or backbone amide to cause nonergodic (before energy randomization) dissociation. Cleavages between every pair of amino acids in mellitin (2.8 kDa) and ubiquitin (8.6 kDa) are represented in their ECD and CAD spectra, providing complete data for their de novo sequencing. Because posttranslational modifications such as carboxylation, glycosylation, and sulfation are less easily lost in ECD than in CAD, ECD assignments of their sequence positions are far more specific.