XTandemPipeline

XTandemPipeline processes peptide and protein identification results from database search engines such as X!Tandem and MASCOT to perform protein inference, manage redundancy, and organize phosphosite identifications for proteomics analyses.

Key Features:

• Protein Inference: Utilizes grouping algorithms based on parsimony principles to determine the minimal set of proteins present across samples.
• Redundancy Management: Identifies and consolidates redundant peptide-to-protein mappings to reduce ambiguity in protein assignments.
• Phosphosite Identification Management: Implements the "phosphoisland" concept to manage overlapping phosphopeptides and classify phosphosites.
• Two-Level Classification — Groups: Collects proteins that share at least one identified peptide.
• Two-Level Classification — Subgroups: Assembles proteins that cannot be distinguished based on the identified peptides.
• Search Engine Compatibility: Processes identification results produced by X!Tandem, MASCOT, and other sequence database search engines.
• Data Export: Generates tabulated files and XML files compatible with PROTICdb and quantification software such as MassChroQ.

Scientific Applications:

• Protein identification consolidation: Consolidating peptide-spectrum matches into protein-level identifications across shotgun proteomics datasets.
• Phosphoproteomics: Managing overlapping phosphopeptides and classifying phosphosites for phosphoproteome studies.
• Downstream data integration: Exporting identification results for repository submission (PROTICdb) and quantitative analysis with MassChroQ.

Methodology:

Processes identification results from X!Tandem and MASCOT, applies grouping algorithms based on parsimony for protein inference, implements the phosphoisland concept for overlapping phosphopeptides, classifies proteins into groups and subgroups, and exports tabulated and XML (PROTICdb/MassChroQ-compatible) files.