PhosphoScoring

Tool to score phosphorylation sites of peptides.

pot. predecessor tools	$\longrightarrow$ PhosphoScoring $\longrightarrow$	pot. successor tools
MascotAdapter (or other ID engines)	$\longrightarrow$ PhosphoScoring $\longrightarrow$	PeptideIndexer

This tool performs phosphorylation analysis and site localization. Input files are an LC-MS/MS data file as well as the corresponding identification file. Firstly, the peptide identifications are mapped onto the spectra. Secondly, the tool uses an implementation of the Ascore according to Beausoleil et al. in order to localize the most probable phosphorylation sites.

For details, see:
Beausoleil et al.: A probability-based approach for high-throughput protein phosphorylation analysis and site localization (Nat. Biotechnol., 2006, PMID: 16964243).

In the output the score of the peptide hit describes the peptide score, which is a weighted average of all ten scores of the selected peptide sequence. For each phosphorylation site an individual Ascore was calculated and listed as meta value of the peptide hit (e.g. AScore_1, AScore_2).

The Ascore results of this TOPP tool differs with the results of the Ascore calculation provided on the website, but it seems that the implementation according to Beausoleil et al. has some calculation errors. It is not possible to recalculate the Ascore using the cumulative binomial probability formula with the given values (see Fig. 3c). In addition the site determining ions calculation seems not reliable, because in some test cases more site determining ions were calculated than it could be possible.

Note: Currently mzIdentML (mzid) is not directly supported as an input/output format of this tool. Convert mzid files to/from idXML using IDFileConverter if necessary.

The command line parameters of this tool are:

PhosphoScoring -- Scores potential phosphorylation sites in order to localize the most probable sites.
Version: 2.3.0 Jan  9 2018, 17:46:23, Revision: 38ae115

Usage:
  PhosphoScoring <options>

Options (mandatory options marked with '*'):
  -in <file>*                           Input file with MS/MS spectra (valid formats: 'mzML')
  -id <file>*                           Identification input file which contains a search against a concatena
                                        ted sequence database (valid formats: 'idXML')
  -out <file>*                          Identification output annotated with phosphorylation scores (valid 
                                        formats: 'idXML')
  -fragment_mass_tolerance <tolerance>  Fragment mass error (default: '0.05')
  -fragment_mass_unit <unit>            Unit of fragment mass error (default: 'Da' valid: 'Da', 'ppm')
  -max_peptide_length <num>             Restrict scoring to peptides with a length shorter than this value 
                                        (default: '40' min: '1')
  -max_num_perm <num>                   Maximum number of permutations a sequence can have (default: '16384' 
                                        min: '1')
                                        
Common TOPP options:
  -ini <file>                           Use the given TOPP INI file
  -threads <n>                          Sets the number of threads allowed to be used by the TOPP tool (defau
                                        lt: '1')
  -write_ini <file>                     Writes the default configuration file
  --help                                Shows options
  --helphelp                            Shows all options (including advanced)

INI file documentation of this tool:

Legend:

required parameter

advanced parameter

+PhosphoScoringScores potential phosphorylation sites in order to localize the most probable sites.

version2.3.0 Version of the tool that generated this parameters file.

++1Instance '1' section for 'PhosphoScoring'

in Input file with MS/MS spectrainput file*.mzML

id Identification input file which contains a search against a concatenated sequence databaseinput file*.idXML

out Identification output annotated with phosphorylation scoresoutput file*.idXML

fragment_mass_tolerance0.05 Fragment mass error

fragment_mass_unitDa Unit of fragment mass errorDa,ppm

max_peptide_length40 Restrict scoring to peptides with a length shorter than this value1:∞

max_num_perm16384 Maximum number of permutations a sequence can have1:∞

log Name of log file (created only when specified)

debug0 Sets the debug level

threads1 Sets the number of threads allowed to be used by the TOPP tool

no_progressfalse Disables progress logging to command linetrue,false

forcefalse Overwrite tool specific checks.true,false

testfalse Enables the test mode (needed for internal use only)true,false