title: Carboxylate and amine terminus directed fragmentations in gaseous dipeptide complexes with copper (II) and diimine ligands formed by electrospray.
abstract: Singly and doubly charged peptide complexes with copper(II) and 2,2'-bipyridyl (bpy) are formed in the gas phase by electrospraying water-methanol solutions containing the components. Collisionally activated dissociations at low kinetic energies of singly charged complexes of the [CuII(peptide-H)(bpy)].+ type provide information about the amino acid sequence for L-Phe-Leu, L-Leu-Phe, L-Phe-Pro, L-Pro-Phe, L-Phe-Met, L-Met-Phe, L-Ser-Phe, L-Asp-Phe, and L-His-Phe. Dissociations of doubly charged complexes of the [CuII(peptide)(bpy).2+ type also allow identification of the N- and C-terminal amino acid residues. Leucine and isoleucine residues are readily distinguished in L-Ala-Leu and L-Ala-Ile through dissociations of their Cu complexes. Ion dissociation mechanisms, as elucidated by deuterium labeling, are discussed.
authors.affiliation: Deartment of Chemistry, University of Washington, Seattle, 98195-1700, USA.
authors.forename: C L
authors.initials: CL
authors.lastname: Gatlin
authors.forename: R D
authors.initials: RD
authors.lastname: Rao
authors.forename: F
authors.initials: F
authors.lastname: Turecek
authors.forename: T
authors.initials: T
authors.lastname: Vaisar
mesh_terms: D000595:Amino Acid Sequence; D002264:Carboxylic Acids / Q000737:chemistry; D003300:Copper; D004151:Dipeptides / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry; D007097:Imines / Q000737:chemistry; D008024:Ligands; D008969:Molecular Sequence Data
chemical_list: D002264:Carboxylic Acids; D004151:Dipeptides; D007097:Imines; D008024:Ligands; D003300:Copper