Leveraging Electron Transfer Dissociation for Site Selective Radical Generation: Applications for Peptide Epimer Analysis

Journal Article · Sat Jul 15 04:00:00 EDT 2017 · Journal of the American Society for Mass Spectrometry

DOI:https://doi.org/10.1007/S13361-017-1627-X· OSTI ID:22776935

Lyon, Yana A.; Beran, Gregory

Traditional electron-transfer dissociation (ETD) experiments operate through a complex combination of hydrogen abundant and hydrogen deficient fragmentation pathways, yielding c and z ions, side-chain losses, and disulfide bond scission. Herein, a novel dissociation pathway is reported, yielding homolytic cleavage of carbon–iodine bonds via electronic excitation. This observation is very similar to photodissociation experiments where homolytic cleavage of carbon–iodine bonds has been utilized previously, but ETD activation can be performed without addition of a laser to the mass spectrometer. Both loss of iodine and loss of hydrogen iodide are observed, with the abundance of the latter product being greatly enhanced for some peptides after additional collisional activation. These observations suggest a novel ETD fragmentation pathway involving temporary storage of the electron in a charge-reduced arginine side chain. Subsequent collisional activation of the peptide radical produced by loss of HI yields spectra dominated by radical-directed dissociation, which can be usefully employed for identification of peptide isomers, including epimers. .

• OSTI ID: 22776935
• Journal Information: Journal of the American Society for Mass Spectrometry, Journal Name: Journal of the American Society for Mass Spectrometry Journal Issue: 7 Vol. 28; ISSN 1044-0305; ISSN JAMSEF
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
CARBON
DISSOCIATION
ELECTRON TRANSFER
EXCITATION
FRAGMENTATION
HYDROGEN IODIDES
IODINE
ISOMERS
MASS SPECTROMETERS
PEPTIDES
PHOTOLYSIS
RADICALS
SPECTRA