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Evaluated Reference MS/MS Spectra Libraries
Current and Future NIST Programs
NIST/EPA/NIH Library of EI Mass Spectra
Search Program/Algorithms
Archive ProgramComputer Assisted Evaluation
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)
Archive Program – MS/MS Mode
Archive Program + MS Interpreter
NIST MS Search Program – MS/MS Library
MW /
Formula /
Name /
Conditions
Levels
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
Input list
Matching peptide and probability scores
Reference spectrum and annotation
Query MS/MSHead to tail sample and reference spectra comparison
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