Side-Chain Fragmentation of Alkylated Cysteine Residues in Electron Capture Dissociation Mass Spectrometry

• Published in: Journal of the American Society for Mass Spectrometry 2006-09, Vol.17 (9), p.1271-1274
• Main Authors: Chalkley, R.J., Brinkworth, C.S., Burlingame, A.L.
• Format: Article
• Language: English
• Subjects: Alkylation; Analytical, structural and metabolic biochemistry; Beta decay; Biological and medical sciences; Chains; Chemical bonds; Cleavage; Cysteine; Cysteine - chemistry; Cystine; Electron capture; Electrons; Fragmentation; Fundamental and applied biological sciences. Psychology; General aspects, investigation methods; Mass spectrometry; Peptide Mapping - methods; Peptides; Proteins; Proteins - chemistry; Proteomics; Residues; Spectrometry, Mass, Electrospray Ionization - methods; Sulfur
• ISSN: 1044-0305; 1879-1123
• DOI: 10.1016/j.jasms.2006.05.017

The recent development of novel fragmentation processes based on either electron capture directly or transfer from an anion show great potential for solving problems in proteomics that are intractable by the more widely employed thermal-based fragmentation processes such as collision induced dissociation. The dominant fragmentation occurring upon electron capture dissociation of peptides is cleavage of N-Cα bonds in the peptide backbone to form c and z· ions. In the case of disulfide-linked peptides, it has also been shown that electron capture on one of the cystine sulfur atoms is favored, resulting in cleavage of the disulfide bond. In this study, we report that electron capture on the sulfur of alkylated cysteine residues is also a dominant process, causing cysteine side-chain loss from z· ions.