title: Charge-site-dependent dissociation of hydrogen-rich radical peptide cations upon vacuum UV photoexcitation.
abstract: Here, 193 nm vacuum ultraviolet photodissociation (VUVPD) was used to investigate the fragmentation of hydrogen-rich radical peptide cations generated by electron transfer reactions. VUVPD offers new insight into the factors that drive radical- and photon-directed processes. The location of a basic Arg site influences photon-activated C(α)-C(O) bond cleavages of singly charged peptide radical cations, an outcome attributed to the initial conformation of the peptide as supported by molecular dynamics simulated annealing and the population of excited states upon UV excitation. This hybrid ETD/VUVPD method was employed to identify phosphorylation sites of the kinase domain of human TRPM7/ChaK1.
authors.affiliation: Department of Chemistry and Biochemistry, The University of Texas at Austin, 1 University Station A5300, Austin, TX 78712, USA.
authors.forename: James A
authors.initials: JA
authors.lastname: Madsen
authors.forename: Ryan R
authors.initials: RR
authors.lastname: Cheng
authors.forename: Tamer S
authors.initials: TS
authors.lastname: Kaoud
authors.forename: Kevin N
authors.initials: KN
authors.lastname: Dalby
authors.forename: Dmitrii E
authors.initials: DE
authors.lastname: Makarov
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Brodbelt
mesh_terms: D000595:Amino Acid Sequence; D002412:Cations / Q000737:chemistry*; D004583:Electrons; D005609:Free Radicals / Q000737:chemistry*; D006801:Humans; D006859:Hydrogen / Q000737:chemistry*; D013058:Mass Spectrometry; D010455:Peptides / Q000737:chemistry*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases; D013056:Spectrophotometry, Ultraviolet; D050053:TRPM Cation Channels / Q000737:chemistry*
chemical_list: D002412:Cations; D005609:Free Radicals; D010455:Peptides; D050053:TRPM Cation Channels; D006859:Hydrogen; D017346:Protein Serine-Threonine Kinases; C486583:TRPM7 protein, human