METHOD AND DEVICE FOR IDENTIFYING MHC CLASS I-PRESENTED PEPTIDES FROM FRAGMENT ION MASS SPECTRA

摘要

The present invention provides a method for determining MHC class I-presented peptides from fragment ion mass spectra, the method comprising:- de novo peptide sequencing from the fragment ion mass spectra to generate candidate peptide sequences;- determining, in a database, matching peptide sequences which match said candidate peptide sequences, wherein the database comprises target peptide sequences and decoy sequences;- classifying the matching peptide sequences into classes of peptides, wherein each class refers to a functionally confined part of the genome;- for each peptide length:estimating a probability distribution of de novo peptide sequencing scores for false hits based on decoy hits, and estimating a probability of true hits based on subtracting of decoy hits from target hits, andfor each class: determining mixture coefficients of a mixture model of the true and false probability distributions; and- filtering the matching peptide sequences using a statistical measure determined based on the deconvolution to determine the MHC class I-presented peptides.