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| MRMDecoy () |
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void | generateDecoys (const OpenMS::TargetedExperiment &exp, OpenMS::TargetedExperiment &dec, const String &method, const double aim_decoy_fraction, const bool switchKR, const String &decoy_tag, const int max_attempts, const double identity_threshold, const double precursor_mz_shift, const double product_mz_shift, const double product_mz_threshold, const std::vector< String > &fragment_types, const std::vector< size_t > &fragment_charges, const bool enable_specific_losses, const bool enable_unspecific_losses, const int round_decPow=-4) const |
| Generate decoys from a TargetedExperiment. More...
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float | AASequenceIdentity (const String &sequence, const String &decoy) const |
| Compute relative identity (relative number of matches of amino acids at the same position) between two sequences. More...
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OpenMS::TargetedExperiment::Peptide | shufflePeptide (OpenMS::TargetedExperiment::Peptide peptide, const double identity_threshold, int seed=-1, const int max_attempts=100) const |
| Shuffle a peptide (with its modifications) sequence. More...
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Public Member Functions inherited from DefaultParamHandler |
| DefaultParamHandler (const String &name) |
| Constructor with name that is displayed in error messages. More...
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| DefaultParamHandler (const DefaultParamHandler &rhs) |
| Copy constructor. More...
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virtual | ~DefaultParamHandler () |
| Destructor. More...
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virtual DefaultParamHandler & | operator= (const DefaultParamHandler &rhs) |
| Assignment operator. More...
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virtual bool | operator== (const DefaultParamHandler &rhs) const |
| Equality operator. More...
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void | setParameters (const Param ¶m) |
| Sets the parameters. More...
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const Param & | getParameters () const |
| Non-mutable access to the parameters. More...
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const Param & | getDefaults () const |
| Non-mutable access to the default parameters. More...
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const String & | getName () const |
| Non-mutable access to the name. More...
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void | setName (const String &name) |
| Mutable access to the name. More...
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const std::vector< String > & | getSubsections () const |
| Non-mutable access to the registered subsections. More...
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| ProgressLogger () |
| Constructor. More...
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| ~ProgressLogger () |
| Destructor. More...
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| ProgressLogger (const ProgressLogger &other) |
| Copy constructor. More...
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ProgressLogger & | operator= (const ProgressLogger &other) |
| Assignment Operator. More...
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void | setLogType (LogType type) const |
| Sets the progress log that should be used. The default type is NONE! More...
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LogType | getLogType () const |
| Returns the type of progress log being used. More...
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void | startProgress (SignedSize begin, SignedSize end, const String &label) const |
| Initializes the progress display. More...
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void | setProgress (SignedSize value) const |
| Sets the current progress. More...
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void | endProgress () const |
| Ends the progress display. More...
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void | nextProgress () const |
| increment progress by 1 (according to range begin-end) More...
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This class generates a TargetedExperiment object with decoys based on a TargetedExperiment object.
There are multiple methods to create the decoy transitions, the simplest ones are reverse and pseudo-reverse which reverse the sequence either completely or leaving the last (tryptic) AA untouched respectively.
Another decoy generation method is "shuffle" which uses an algorithm similar to the one described in Lam, Henry, et al. (2010). "Artificial decoy spectral libraries for false discovery rate estimation in spectral library searching in proteomics". Journal of Proteome Research 9, 605-610. It shuffles the amino acid sequence and shuffles the fragment ion intensities accordingly, however for this to work the fragment ions need to be matched to annotated before.
First, the algorithm goes through all peptides and applies the decoy method to the target peptide sequence (pseudo-reverse, reverse or shuffle) in order to produce the decoy sequence. Then, for each peptide, the fragment ions in the target library are matched to their most likely origin (e.g. the ions are annotated with their ion series (a,b,y) and the fragment number and optionally a neutral loss (10 different neutral losses are currently implemented)). For each fragment ion from the target peptide, an equivalent ion is created for the decoy peptide with the same intensity (e.g. if the target peptide sequence has a b5 ion with a normalized intensity of 200, an equivalent b5 ion for the decoy sequence is created and assigned the intensity 200). Optionally, the m/z values are corrected to reflect the theoretical value rather than the experimental value in the library.
void generateDecoys |
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const OpenMS::TargetedExperiment & |
exp, |
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OpenMS::TargetedExperiment & |
dec, |
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const String & |
method, |
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const double |
aim_decoy_fraction, |
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const bool |
switchKR, |
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const String & |
decoy_tag, |
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const int |
max_attempts, |
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const double |
identity_threshold, |
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const double |
precursor_mz_shift, |
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const double |
product_mz_shift, |
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const double |
product_mz_threshold, |
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const std::vector< String > & |
fragment_types, |
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const std::vector< size_t > & |
fragment_charges, |
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const bool |
enable_specific_losses, |
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const bool |
enable_unspecific_losses, |
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const int |
round_decPow = -4 |
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Generate decoys from a TargetedExperiment.
Will generate decoy peptides for each target peptide provided in exp and write them into the decoy experiment.
Valid methods: shuffle, reverse, pseudo-reverse
If theoretical is true, the target transitions will be returned but their masses will be adjusted to match the theoretical value of the fragment ion that is the most likely explanation for the product.
mz_threshold is used for the matching of theoretical ion series to the observed one
To generate decoys with different precursor mass, use the "switchKR" flag which switches terminal K/R (switches K to R and R to K). This generates different precursor m/z and ensures that the y ion series has a different mass. For a description of the procedure, see (supplemental material)
Bruderer et al. Mol Cell Proteomics. 2017. 10.1074/mcp.RA117.000314.