*2.7. Database Search and Peptide Identification*

In order to permit peptide identification two proteomic tools, Proteome Discoverer software (version 1.4, Thermo Fisher Scientific, Waltham, MA, USA) and the Mascot Search engine server (version 2.2.4, MatrixScience, London, UK) were utilized for processing raw LC-MS/MS data files given by Xcalibur software (version 2.2 SP1, Thermo Fisher Scientific, Waltham, MA, USA). Protein identification against the SwissProt database (version 20180703; 597363 sequences; SIB Swiss Institute of Bioinformatics, Lausanne, Switzerland) was performed using the following parameters: no enzyme, precursor tolerance 10 ppm and fragment tolerance 0.6 Da. Oxidation of methionine was set as

variable modification. The Percolator algorithm was used to assess the false-discovery rate and filter the results (FDR < 0.01). Proteins were grouped in protein families according to the principle of maximum parsimony.
