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Improving CID, HCD, and ETD FT MS/MS degradome-peptidome identifications using high accuracy mass information

Journal Article · · Journal of Proteome Research
DOI:https://doi.org/10.1021/pr200597j· OSTI ID:1030469

The peptidome (i.e. processed and degraded forms of proteins) of e.g. blood can potentially provide insights into disease processes, as well as a source of candidate biomarkers that are unobtainable using conventional bottom-up proteomics approaches. MS dissociation methods, including CID, HCD, and ETD, can each contribute distinct identifications using conventional peptide identification methods (Shen et al. J. Proteome Res. 2011), but such samples still pose significant analysis and informatics challenges. In this work, we explored a simple approach for better utilization of high accuracy fragment ion mass measurements provided e.g. by FT MS/MS and demonstrate significant improvements relative to conventional descriptive and probabilistic scores methods. For example, at the same FDR level we identified 20-40% more peptides than SEQUEST and Mascot scoring methods using high accuracy fragment ion information (e.g., <10 mass errors) from CID, HCD, and ETD spectra. Species identified covered >90% of all those identified from SEQUEST, Mascot, and MS-GF scoring methods. Additionally, we found that the merging the different fragment spectra provided >60% more species using the UStags method than achieved previously, and enabled >1000 peptidome components to be identified from a single human blood plasma sample with a 0.6% peptide-level FDR, and providing an improved basis for investigation of potentially disease-related peptidome components.

Research Organization:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Organization:
USDOE
DOE Contract Number:
AC05-76RL01830
OSTI ID:
1030469
Report Number(s):
PNNL-SA-81060; 40072; KP1601010
Journal Information:
Journal of Proteome Research, Journal Name: Journal of Proteome Research
Country of Publication:
United States
Language:
English