title: Charge remote fragmentation in electron capture and electron transfer dissociation.
abstract: Secondary fragmentations of three synthetic peptides (human alphaA crystallin peptide 1-11, the deamidated form of human betaB2 crystallin peptide 4-14, and amyloid beta peptide 25-35) were studied in both electron capture dissociation (ECD) and electron-transfer dissociation (ETD) mode. In ECD, in addition to c and z. ion formations, charge remote fragmentations (CRF) of z. ions were abundant, resulting in internal fragment formation or partial/entire side-chain losses from amino acids, sometimes several residues away from the backbone cleavage site, and to some extent multiple side-chain losses. The internal fragments were observed in peptides with basic residues located in the middle of the sequences, which was different from most tryptic peptides with basic residues located at the C-terminus. These secondary cleavages were initiated by hydrogen abstraction at the alpha-, beta-, or gamma-position of the amino acid side chain. In comparison, ETD generates fewer CRF fragments than ECD. This secondary cleavage study will facilitate ECD/ETD spectra interpretation, and help de novo sequencing and database searching.
authors.affiliation: Mass Spectrometry Resource, Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts, USA.
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Li
authors.forename: Cheng
authors.initials: C
authors.lastname: Lin
authors.forename: Liang
authors.initials: L
authors.lastname: Han
authors.forename: Catherine E
authors.initials: CE
authors.lastname: Costello
authors.forename: Peter B
authors.initials: PB
authors.lastname: O'Connor
mesh_terms: D000595:Amino Acid Sequence; D004579:Electron Transport; D008969:Molecular Sequence Data; D010449:Peptide Mapping / Q000379:methods*; D010455:Peptides / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D010455:Peptides