You can visually verify matches between measured spectra from your experiment and the reference spectra in the spectrum library for peptides identified with the MSPepSearch node. In the Peptide Spectrum Match Identification Details view, you can display a mirror plot of the matching peptides.

Procedure

  1. Open a result file and select the PSMs tab.
  2. Double-click the row of interest.
  3. The Peptide Spectrum Match Identification Details view opens.
  4. From the Peptide Spectrum Match Identification Details dialog box, select the Show Reference Spectrum checkbox.
  5. In the Ref Spectrum Source dropdown, choose either From Identifying Node or Spectrum Library.
  6. Mirror plot in the Peptide Spectrum Match Identification Details view for a PSM produced by MSPepSearch.
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    No.DescriptionNo.Description

    1

    Measured spectrum

    2

    Reference spectrum

The application displays the reference spectrum using intensities multiplied by –1 in the same plot as the measured spectrum. In the reference spectrum, it also labels peaks of both the a, b, and c ion series and the x, y, and z ion series, as well as the peaks from the precursor peptide.

NOTE

It does not display labels for all fragments with a mass difference, isotope peaks, and “?” peaks in the spectrum library.