NOTE: unfortunately these spectrum files are in the old SEQUEST .dta format.
A. Keller, S. Purvine, A.I. Nesvizhskii, S. Stolyar, D.R. Goodlett, and E. Kolker, "Experimental Protein Mixture for Validating Tandem Mass Spectra Analysis", OMICS 6(2), 207-212 (2002). https://pubmed.ncbi.nlm.nih.gov/12143966/ (PDF).
If you're interested in this data, send me (engj@uw.edu) or anyone else at the UWPR an email and we will supply you a download link. These files are not available/linked here direct download to avoid constant downloads by data crawlers.
The css used for rendering these pages is horrible; this will be fixed soon.
The content:
spectrum charge_state protein peptide
The ending '...2/3' in the spectrum name indicates that the same MS/MS spectrum was searched using SEQUEST twice, once assuming it was a 2+ precursor ion (spectrum name ending with .2) , and once assuming it was a 3+ ion (spectrum name ending with .3). The number following the spectrum name indicates what the correct charge state.
For example,
./sergei_digest_A_full_01.0469.0471.2/3 2 sp|P02666|CASB_BOVIN K.VKEAMAPK.H
means that the spectrum 'sergei_digest_A_full_01.0469.0471.2' was assigned a peptide K.VKEAMAPK.H corresponding with CASB_BOVIN protein (one of the 18 control proteins), and that that identification was a correct one.