High-Energy Electron Transfer Dissociation (HE-ETD) Using Alkali Metal Targets for Sequence Analysis of Post-Translational Peptides

• Published in: Journal of the American Society for Mass Spectrometry 2010-09, Vol.21 (9), p.1482-1489
• Main Authors: Hayakawa, Shigeo, Matsumoto, Shinya, Hashimoto, Mami, Iwamoto, Kenichi, Nagao, Hirofumi, Toyoda, Michisato, Shigeri, Yasushi, Tajiri, Michiko, Wada, Yoshinao
• Format: Article
• Language: English
• Subjects: Activation; Alkali metals; Amino acids; Aminoacids, peptides. Hormones. Neuropeptides; Analytical Chemistry; Analytical, structural and metabolic biochemistry; Anions; Beta decay; Bioinformatics; Biological and medical sciences; Biotechnology; Cesium - chemistry; Chemistry; Chemistry and Materials Science; Electron capture; Electron transfer; Electrons; Energy consumption; Energy of dissociation; Fundamental and applied biological sciences. Psychology; Mass spectrometry; Organic Chemistry; Peptides; Phosphates; Phosphopeptides - analysis; Phosphopeptides - metabolism; Phosphorylation; Position (location); Protein Processing, Post-Translational; Proteins; Proteomics; Proteomics - methods; Spectrometry, Mass, Electrospray Ionization - methods; Xenon - chemistry
• ISSN: 1044-0305; 1879-1123
• DOI: 10.1016/j.jasms.2010.05.010

Post-translational modifications (PTMs) of proteins are important in the activation, localization, and regulation of protein function in vivo. The usefulness of electron capture dissociation (ECD) and electron-transfer dissociation (ETD) in tandem mass spectrometry (MS/MS) using low-energy (LE) trap type mass spectrometer is associated with no loss of a labile PTM group regarding peptide and protein sequencing. The experimental results of high-energy (HE) collision induced dissociation (CID) using the Xe and Cs targets and LE-ETD were compared for doubly-phosphorylated peptides TGFLT(p)EY(p)VATR ( 1). Although HE-CID using the Xe target did not provide information on the amino acid sequence, HE-CID using the Cs target provided all the z-type ions without loss of the phosphate groups as a result of HE-ETD process, while LE-ETD using fluoranthene anion gave only z-type ions from z 5 to z 11. The difference in the results of HE-CID between the Xe and Cs targets demonstrated that HE-ETD process with the Cs target took place much more dominantly than collisional activation. The difference between HE-ETD using Cs targets and LE-ETD using the anion demonstrated that mass discrimination was much weaker in the high-energy process. HE-ETD was also applied to three other phosphopeptides YGGMHRQEX(p)VDC ( 2: X = S, 3: X = T, 4: X = Y). The HE-CID spectra of the doubly-protonated phosphopeptides (= [M + 2H] 2+) of 2, 3, and 4 using the Cs target showed a very similar feature that the c-type ions from c 7 to c 11 and the z-type ions from z 7 to z 11 were formed via N–Cα bond cleavage without a loss of the phosphate group. High-energy (HE) collision induced dissociation (CID) using the Xe and Cs targets and LE-ETD were compared for phosphorylated peptides TGFLT(p)EY(p)VATR and YGGMHRQEX(p)VDC ( 2: X = S, 3: X = T, 4: X = Y).