Effect of the position of a basic amino acid onC-terminal rearrangement of protonated peptides upon collision-induced dissociation

✍ Scribed by Gonzalez, Javier; Besada, Vladimir; Garay, Hilda; Reyes, Osvaldo; Padron, Gabriel; Tambara, Yanet; Takao, Toshifumi; Shimonishi, Yasutsugu

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 632 KB
• Volume: 31
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/(sici)1096-9888(199602)31:2<150::aid-jms287>3.0.co;2-5

✦ Synopsis

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 BIE-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 s q w n c e and its basicity have a significant influence on the rearrangement. Arginine (Arg) located a t 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 carhonyl group via a salt bridge which is tightly formed in vaeuo 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.