title: Structures of alpha-type ions formed in the 157 nm photodissociation of singly-charged peptide ions.
abstract: One hundred fifty-seven nm photodissociation of singly-charged peptide ions induces the cleavage of alpha-carbon to carbonyl-carbon bonds along the backbone. a(n) + 1 radical ions are observed as the primary photolysis products of peptides with N-terminal arginines in a linear ion trap mass spectrometer. The radical elimination pathways undertaken by the a(n) + 1 radical ions to form more stable even-electron species are studied in hydrogen-deuterium (H/D) exchange experiments. Two types of a(n) ions along with d-type ions are observed as secondary elimination products. The relative abundance of each depends on the C-terminal residue of the radical fragment ion.
authors.affiliation: Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA.
authors.forename: Liangyi
authors.initials: L
authors.lastname: Zhang
authors.forename: Weidong
authors.initials: W
authors.lastname: Cui
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Thompson
authors.forename: James P
authors.initials: JP
authors.lastname: Reilly
mesh_terms: D000595:Amino Acid Sequence / Q000528:radiation effects; D005609:Free Radicals; D007477:Ions; D008027:Light; D008969:Molecular Sequence Data; D010449:Peptide Mapping / Q000379:methods*; D010455:Peptides / Q000737:chemistry* / Q000528:radiation effects*; D010777:Photochemistry / Q000379:methods*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D055672:Static Electricity
chemical_list: D005609:Free Radicals; D007477:Ions; D010455:Peptides