Sequential abundant ion fragmentation analysis (SAIFA): an alternative approach for phosphopeptide identification using an ion trap mass spectrometer. Anal Biochem 2011 Nov 15;418(2):197-203
Date
08/23/2011Pubmed ID
21855524Pubmed Central ID
PMC3188319DOI
10.1016/j.ab.2011.07.026Scopus ID
2-s2.0-80052778411 (requires institutional sign-in at Scopus site) 4 CitationsAbstract
Phosphorylation has been the most studied of all the posttranslational modifications of proteins. Mass spectrometry has emerged as a powerful tool for phosphomapping on proteins/peptides. Collision-induced dissociation (CID) of phosphopeptides leads to the loss of phosphoric or metaphosphoric acid as a neutral molecule, giving an intense neutral loss product ion in the mass spectrum. Dissociation of the neutral loss product ion identifies peptide sequence. This method of data-dependent constant neutral loss (DDNL) scanning analysis has been commonly used for mapping phosphopeptides. However, preferential losses of groups other than phosphate are frequently observed during CID of phosphopeptides. Ions that result from such losses are not identified during DDNL analysis due to predetermined scanning for phosphate loss. In this study, we describe an alternative approach for improved identification of phosphopeptides by sequential abundant ion fragmentation analysis (SAIFA). In this approach, there is no predetermined neutral loss molecule, thereby undergoing sequential fragmentation of abundant peak, irrespective of the moiety lost during CID. In addition to improved phosphomapping, the method increases the sequence coverage of the proteins identified, thereby increasing the confidence of protein identification. To the best of our knowledge, this is the first report to use SAIFA for phosphopeptide identification.
Author List
Chesnik M, Halligan B, Olivier M, Mirza SPMESH terms used to index this publication - Major topics in bold
Amino Acid SequenceCaseins
Ions
Mass Spectrometry
Phosphopeptides
Protein Processing, Post-Translational
Proteomics
