Selection of Collision Energies in Proteomics Mass Spectrometry Experiments for Best Peptide Identification: Study of Mascot Score Energy Dependence Reveals Double Optimum

Ágnes Révész, Tibor András Rokob, Dany Jeanne Dit Fouque, Lilla Turiák, Antony Memboeuf, Károly Vékey, László Drahos

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Collision energy is a key parameter determining the information content of beam-type collision induced dissociation tandem mass spectrometry (MS/MS) spectra, and its optimal choice largely affects successful peptide and protein identification in MS-based proteomics. For an MS/MS spectrum, quality of peptide match based on sequence database search, often characterized in terms of a single score, is a complex function of spectrum characteristics, and its collision energy dependence has remained largely unexplored. We carried out electrospray ionization-quadrupole-time of flight (ESI-Q-TOF)-MS/MS measurements on 2807 peptides from tryptic digests of HeLa and E. coli at 21 different collision energies. Agglomerative clustering of the resulting Mascot score versus energy curves revealed that only few of them display a single, well-defined maximum; rather, they feature either a broad plateau or two clear peaks. Nonlinear least-squares fitting of one or two Gaussian functions allowed the characteristic energies to be determined. We found that the double peaks and the plateaus in Mascot score can be associated with the different energy dependence of b- and y-type fragment ion intensities. We determined that the energies for optimum Mascot scores follow separate linear trends for the unimodal and bimodal cases with rather large residual variance even after differences in proton mobility are taken into account. This leaves room for experiment optimization and points to the possible influence of further factors beyond m/z.

Original languageEnglish
Pages (from-to)1898-1906
Number of pages9
JournalJournal of Proteome Research
Volume17
Issue number5
DOIs
Publication statusPublished - May 4 2018

Keywords

  • Mascot score
  • collision energy
  • curve fitting
  • mass spectrometry
  • optimization
  • peptide fragmentation

ASJC Scopus subject areas

  • Biochemistry
  • Chemistry(all)

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