HI-bone: a scoring system for identifying phenylisothiocyanate-derivatized peptides based on precursor mass and high intensity fragment ions

Anal Chem. 2013 Apr 2;85(7):3515-20. doi: 10.1021/ac303239g. Epub 2013 Mar 20.

Abstract

Peptide sequence matching algorithms used for peptide identification by tandem mass spectrometry (MS/MS) enumerate theoretical peptides from the database, predict their fragment ions, and match them to the experimental MS/MS spectra. Here, we present an approach for scoring MS/MS identifications based on the high mass accuracy matching of precursor ions, the identification of a high intensity b1 fragment ion, and partial sequence tags from phenylthiocarbamoyl-derivatized peptides. This derivatization process boosts the b1 fragment ion signal, which turns it into a powerful feature for peptide identification. We demonstrate the effectiveness of our scoring system by implementing it on a computational tool called "HI-bone" and by identifying mass spectra of an Escherichia coli sample acquired on an Orbitrap Velos instrument using Higher-energy C-trap dissociation. Following this strategy, we identified 1614 peptide spectrum matches with a peptide false discovery rate (FDR) below 1%. These results were significantly higher than those from Mascot and SEQUEST using a similar FDR.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms
  • Amino Acid Sequence
  • Escherichia coli / chemistry
  • Escherichia coli Proteins / chemistry
  • Humans
  • Ions / chemistry
  • Isothiocyanates / chemistry*
  • Molecular Sequence Data
  • Peptides / analysis*
  • Proteomics / methods*
  • Software
  • Tandem Mass Spectrometry / methods*

Substances

  • Escherichia coli Proteins
  • Ions
  • Isothiocyanates
  • Peptides
  • phenylisothiocyanate