title: Effect of the position of a basic amino acid on C-terminal rearrangement of protonated peptides upon collision-induced dissociation.
abstract: Internal rearrangement involving the loss of the C-terminal amino acid residue upon collision-induced dissociation (CID) or metastable decomposition was studied for protonated peptides. To investigate the structural characteristics of peptides responsible for this rearrangement, a series of synthetic peptides were prepared and subjected to B/E-linked scan or tandem mass spectrometric analyses using a four-sector instrument. The results showed that the position of a basic amino acid in the peptide sequence and its basicity have a significant influence on the rearrangement. Arginine (Arg) located at the n-1 position facilitates the rearrangement with about twice as many rearrangement ions as is observed for the other Arg-containing peptides. This can be attributed to the interaction of a positively charged guanidino group of Arg with its own carbonyl group via a salt bridge which is tightly formed in vacuo between a guanidino and carboxylate groups, the mechanism of which is analogous to that previously proposed for the formation of similar rearrangement ions observed in the spectra of metal-cationized peptides. This association would result in the facile attack of the C-terminal hydroxyl group on the penultimate carbonyl group, leading to the rearrangement. In addition, the rearrangement ion was observed both in metastable decomposition and high-energy CID spectra obtained by B/E-linked scan analyses without or with gas, respectively, but in a sequence dependent manner.
authors.affiliation: Center for Genetic Engineering and Biotechnology, Havana, Cuba.
authors.forename: J
authors.initials: J
authors.lastname: Gonzalez
authors.forename: V
authors.initials: V
authors.lastname: Besada
authors.forename: H
authors.initials: H
authors.lastname: Garay
authors.forename: O
authors.initials: O
authors.lastname: Reyes
authors.forename: G
authors.initials: G
authors.lastname: Padron
authors.forename: Y
authors.initials: Y
authors.lastname: Tambara
authors.forename: T
authors.initials: T
authors.lastname: Takao
authors.forename: Y
authors.initials: Y
authors.lastname: Shimonishi
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry; D000805:Angiotensin III / Q000737:chemistry; D001120:Arginine / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D006514:Hepatitis B Surface Antigens / Q000737:chemistry; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009842:Oligopeptides / Q000138:chemical synthesis / Q000737:chemistry*; D010103:Oxygen Isotopes; D010446:Peptide Fragments / Q000737:chemistry*; D011994:Recombinant Proteins / Q000737:chemistry
chemical_list: D000596:Amino Acids; D006514:Hepatitis B Surface Antigens; D009842:Oligopeptides; D010103:Oxygen Isotopes; D010446:Peptide Fragments; D011994:Recombinant Proteins; D000805:Angiotensin III; D001120:Arginine