Paketti: tandem-mass (1:201702011-1build1)

mass spectrometry software for protein identification

X! Tandem can match tandem mass spectra with peptide sequences, in a process that is commonly used to perform protein identification.

This software has a very simple, unsophisticated application programming interface (API): it simply takes an XML file of instructions on its command line, and outputs the results into an XML file, which has been specified in the input XML file. The output file format is described at http://www.thegpm.org/docs/X_series_output_form.pdf.

Unlike some earlier generation search engines, all of the X! Series search engines calculate statistical confidence (expectation values) for all of the individual spectrum-to-sequence assignments. They also reassemble all of the peptide assignments in a data set onto the known protein sequences and assign the statistical confidence that this assembly and alignment is non-random. The formula for which can be found here. Therefore, separate assembly and statistical analysis software, e.g. PeptideProphet and ProteinProphet, do not need to be used.