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Evaluated Reference MS/MS Spectra Libraries. Current and Future NIST Programs. NIST/EPA/NIH Library of EI Mass Spectra. Archive Program Computer Assisted Evaluation. Search Program/Algorithms. NIST MS/MS Library. June 2005 - 5,191 Spectra 1,920 Precursor ions (incl. 292 Anions)
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Evaluated Reference MS/MS Spectra Libraries Current and Future NIST Programs
NIST/EPA/NIH Library of EI Mass Spectra Archive ProgramComputer Assisted Evaluation Search Program/Algorithms
NIST MS/MS Library • June 2005 - 5,191 Spectra • 1,920 Precursor ions (incl. 292 Anions) • From NIST, Contributors and literature • Ion trap, Triple Quad, … • New data structure/software • Energy and precursor ion variations • Evaluation/Search logic • Range of Energies (collision cell)
NIST MS Search Program – MS/MS Library Levels MW / Formula / Name / Conditions
NIST Library of Peptide Ion Fragmentation Spectra • Peptide sequences are used to infer proteins – from protein digests • Derived from ‘Shotgun’ proteomics • Identifications originate from sequence-based search method • Human, Yeast, Selected Proteins, … • 90,000 Consensus spectra • Ion trap and qtof spectra (tof/tof soon) of ESI and MALDI generated ions
Processing Pipeline • From Raw data to Identified Proteins • Complex series of data transformations • Peptide sequences are identified by matching m/z values against all possible sequences • Consensus spectra extracted from pipeline • New QA/QC methods • Library re-inserted to pipeline for faster, more reliable, more sensitive IDs
Head to tail sample and reference spectra comparison Input list Query MS/MS Matching peptide and probability scores Reference spectrum and annotation
Fragmentation depends on energy/time • FT-ICR • Lowest energies (SORI, IRMPD, SID, …) • Ion Trap • Allows multiple stages of fragmentation • Collision cell (Low E) • Dissociation increases with energy • PSD • Low energy, limited energy/time • Collision cell (High E) • Single collision, wide E distribution