title: Dissociation mechanisms and implication for the presence of multiple conformations for peptide ions with arginine at the C-terminus: time-resolved photodissociation study.
abstract: Time-resolved photodissociation (PD) patterns of singly protonated peptides with arginine at the C-terminus (C-arg peptide ions) have been used to classify the dissociation channels into two categories, i.e. high-energy channels generating v, w and x and low-energy ones generating b, y and z. x + 1 formed by C(alpha)-CO cleavage seems to be the intermediate ion in high-energy channels just as a + 1 is for N-arg peptide ions. Difference in time-resolved pattern indicates that the two sets of channels, high- and low-energy ones, are not in direct competition. Noncompetitive dissociation is also indicated by the observation of anomalous effect of matrix used in matrix-assisted laser desorption ionization, a cooler matrix generating more high-energy product ions both in spontaneous dissociation and in PD. Results from detailed investigation suggest that the two sets of channels start from two (or more) different conformations.
authors.affiliation: Department of Chemistry, Seoul National University, Seoul 151-742, Korea.
authors.forename: So Hee
authors.initials: SH
authors.lastname: Yoon
authors.forename: Jeong Hee
authors.initials: JH
authors.lastname: Moon
authors.forename: Myung Soo
authors.initials: MS
authors.lastname: Kim
mesh_terms: D001120:Arginine / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D008968:Molecular Conformation; D010455:Peptides / Q000737:chemistry*; D055668:Photochemical Processes; D011522:Protons; D053719:Tandem Mass Spectrometry
chemical_list: D007477:Ions; D010455:Peptides; D011522:Protons; D001120:Arginine