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Effect of the position of a basic amino acid on C ‐terminal rearrangement of protonated peptides upon collision‐induced dissociation
Author(s) -
Gonzalez Javier,
Besada Vladimir,
Garay Hilda,
Reyes Osvaldo,
Padron Gabriel,
Tambara Yanet,
Takao Toshifumi,
Shimonishi Yasutsugu
Publication year - 1996
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/(sici)1096-9888(199602)31:2<150::aid-jms287>3.0.co;2-5
Subject(s) - chemistry , protonation , dissociation (chemistry) , stereochemistry , collision induced dissociation , peptide , salt bridge , carboxylate , rearrangement reaction , ion , amino acid , tandem mass spectrometry , mass spectrometry , organic chemistry , mutant , gene , catalysis , biochemistry , chromatography
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.