Sequencing of sulfonic acid derivatized peptides by electrospray mass spectrometry

✍ Scribed by Mark D. Bauer; Yiping Sun; Thomas Keough; Martin P. Lacey

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 114 KB
• Volume: 14
• Category: Article
• ISSN: 0951-4198
• DOI: 10.1002/(sici)1097-0231(20000530)14:10<924::aid-rcm967>3.0.co;2-x

✦ Synopsis

We report the application of nanoelectrospray ionization tandem mass spectrometry (nES-MS/MS) and capillary LC/microelectrospray MS/MS (cLC/&mgrES-MS/MS) for sequencing sulfonic acid derivatized tryptic peptides. These derivatives were specifically prepared to facilitate low-energy charge-site-initiated fragmentation of C-terminal arginine-containing peptides, and to enhance the selective detection of a single series of y-type fragment ions. Both singly and doubly protonated peptides were analyzed by MS/MS and the results were compared with those from their derivatized counterparts. Model peptides and peptides from tryptic digests of gel-isolated proteins were analyzed. Derivatized singly protonated peptides fragment in the same way by nES-MS/MS as they do by post-source decay matrix-assisted laser desorption/ionization mass spectrometry (PSD-MALDI-MS). They produce fragment ion spectra dominated by y-ions, and the simplified spectra are readily interpreted de novo. Doubly protonated peptides fragment in much the same way as their non-derivatized doubly protonated counterparts. The fragmentation of doubly protonated derivatives is especially useful for sequencing peptides that possess a proline residue near the N-terminus of the molecule. The singly protonated forms of these proline-containing derivatives often show enhanced fragmentation on the N-terminal side of the proline and considerably reduced fragmentation on the C-terminal side. In addition, sulfonic acid derivatization increases the in-source fragmentation of arginine-containing peptides. This could be useful for sequence verification and sequence tagging for use in single stage mass spectrometry. Copyright 2000 John Wiley & Sons, Ltd.