Basic Residues Affect the Isomerizations and Dissociations of Peptide Radical Cations

The goal of this presentation aims to provide a fundamental understanding of the formation, interconversion, and fragmentation of radical peptide ions. These processes are the scientific basis underlying radical peptide/protein sequencing in the gas phase—one of the important emerging analytical techniques used in proteomics applications—and have been used as models for molecular wires in fundamental studies of charge transfer in biological systems. A fundamental understanding of the mechanisms, energetics, and kinetics of specific dissociation pathways of the radical cations of peptides; particular emphasis will be placed on peptide radical cations with well defined initial radical sites—using a combination of experimental and computational approaches. The non-convertible isomeric radical cationic glycylglycyltryptophans G^•GW^＋ and GGW^•＋, with their initial radical sites at the -carbon atom and the 3-methylindole ring, respectively, fragment differently because their isomerization is slightly higher in energy than their competitive dissociation processes. In this study, we first performed low-energy collision-induced dissociation (CID) experiments to examine the effect of the basicity of the terminal amino acid residue on the fragmentations of {{if article.abstractinfoEn && article.abstractinfoEn != ""}}

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