UV Action Spectroscopy of Gas-Phase Peptide Radicals

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• 作者：Huong T. H. Nguyen ; Christopher J. Shaffer ; Robert Pepin ; Franti拧ek Ture膷ek
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2015
• 出版时间：December 3, 2015
• 年：2015
• 卷：6
• 期：23
• 页码：4722-4727
• 全文大小：446K
• ISSN：1948-7185

文摘

UV photodissociation (UVPD) action spectroscopy is reported to provide a sensitive tool for the detection of radical sites in gas-phase peptide ions. UVPD action spectra of peptide cation radicals of the z-type generated by electron-transfer dissociation point to the presence of multiple structures formed as a result of spontaneous isomerizations by hydrogen atom migration. N-terminal C_伪 radicals are identified as the dominant components, but the content of isomers differing in the radical defect position in the backbone or side chain depends on the nature of the aromatic residue with phenylalanine being more prone to isomerization than tryptophan. These results illustrate that spontaneous hydrogen atom migrations can occur in peptide cation-radicals upon electron-transfer dissociation.