EMBOSS: mwfilter

| mwfilter

## Function

Filter noisy data from molecular weights file

## Description

mwfilter removes unwanted (noisy) data from mass spectrometry output in proteomics. It reads an input file with a list of experimental molecular weights and writes the same data to an output file but with unwanted (noisy) data removed, at a specified ppm tolerance. Optionally the deleted molecular weights are shown. It removes those molecular weights which are:

- Contaminating trypsin or keratin
- Modified oxy-methionine or oxy-threonine
- Peaks associated with sodium ions.

The last two operations can be done as most peaks are reported in both modified and unmodified forms. Removal of modified peaks aids in database searching for protein identification.

## Usage

Here is a sample session with mwfilter

    % mwfilter
    Filter noisy data from molecular weights file
    Molecular weights file: molwts.dat
    Ppm tolerance [50.0]:
    Molecular weights output file [molwts.mwfilter]:

Go to the input files for this example
Go to the output files for this example

## Command line arguments

       Standard (Mandatory) qualifiers:
      [-infile]            infile     Molecular weights file
       -tolerance          float      [50.0] Ppm tolerance (Any numeric value)
      [-outfile]           outfile    [*.mwfilter] Molecular weights output file

       Additional (Optional) qualifiers:
       -showdel            boolean    [N] Output deleted mwts

       Advanced (Unprompted) qualifiers:
       -datafile           datafile   [Emwfilter.dat] Molecular weight standards
                                      data file

       Associated qualifiers:

       "-outfile" associated qualifiers
       -odirectory2        string     Output directory

       General qualifiers:
       -auto               boolean    Turn off prompts
       -stdout             boolean    Write first file to standard output
       -filter             boolean    Read first file from standard input, write
                                      first file to standard output
       -options            boolean    Prompt for standard and additional values
       -debug              boolean    Write debug output to program.dbg
       -verbose            boolean    Report some/full command line options
       -help               boolean    Report command line options. More
                                      information on associated and general
                                      qualifiers can be found with -help -verbose
       -warning            boolean    Report warnings
       -error              boolean    Report errors
       -fatal              boolean    Report fatal errors
       -die                boolean    Report dying program messages

Standard (Mandatory) qualifiers | Allowed values | Default
--- | --- | ---
[-infile] (Parameter 1) | Molecular weights file | Input file | Required
-tolerance | Ppm tolerance | Any numeric value | 50.0
[-outfile] (Parameter 2) | Molecular weights output file | Output file | <*>.mwfilter
Additional (Optional) qualifiers | Allowed values | Default
-showdel | Output deleted mwts | Boolean value Yes/No | No
Advanced (Unprompted) qualifiers | Allowed values | Default
-datafile | Molecular weight standards data file | Data file | Emwfilter.dat

## Input file format

### Input files for usage example

### File: molwts.dat

    874.364756
    927.450380
    1045.572
    1068.397129
    1121.431124
    1163.584593
    1305.660840
    1428.596448
    1479.748341
    1502.549157
    1554.591658
    1567.686209
    1576.708354
    1639.868056
    1748.611920
    1753.745298
    1880.841178
    2383.99

The input file is a simple list of the experimental molecular weights.
There should be one weight per line.

Comments in the data file start with a '#' character in the first column.
Blank lines are ignored.

## Output file format

The output is a list of the molecular weights with the unwanted (noisy) data removed.

### Output files for usage example

### File: molwts.mwfilter

    874.364756
    927.450380
    1068.397129
    1121.431124
    1163.584593
    1305.660840
    1428.596448
    1479.748341
    1502.549157
    1554.591658
    1567.686209
    1576.708354
    1639.868056
    1748.611920
    1753.745298
    1880.841178

## Data files

The program reads the data file Emwfilter.dat for the molecular weights of items to be deleted from the experimental data.

EMBOSS data files are distributed with the application and stored in the standard EMBOSS data directory, which is defined by the EMBOSS environment variable EMBOSS_DATA.

To see the available EMBOSS data files, run:

    % embossdata -showall

To fetch one of the data files (for example 'Exxx.dat') into your current directory for you to inspect or modify, run:

    % embossdata -fetch -file Exxx.dat

Users can provide their own data files in their own directories. Project specific files can be put in the current directory, or for tidier directory listings in a subdirectory called ".embossdata". Files for all EMBOSS runs can be put in the user's home directory, or again in a subdirectory called ".embossdata".

The directories are searched in the following order:

- . (your current directory)
- .embossdata (under your current directory)
- ~/ (your home directory)
- ~/.embossdata

## Notes

None.

## References

None.

## Warnings

None.

## Diagnostic Error Messages

None.

## Exit status

It always exits with status 0.

## Known bugs

None.

## See also

Program name | Description
--- | ---
backtranambig | Back-translate a protein sequence to ambiguous nucleotide sequence
backtranseq | Back-translate a protein sequence to a nucleotide sequence
charge | Draw a protein charge plot
checktrans | Reports STOP codons and ORF statistics of a protein
compseq | Calculate the composition of unique words in sequences
emowse | Search protein sequences by digest fragment molecular weight
freak | Generate residue/base frequency table or plot
iep | Calculate the isoelectric point of proteins
mwcontam | Find weights common to multiple molecular weights files
octanol | Draw a White-Wimley protein hydropathy plot
pepinfo | Plot amino acid properties of a protein sequence in parallel
pepstats | Calculates statistics of protein properties
pepwindow | Draw a Kyte-Doolittle hydropathy plot for a protein sequence
pepwindowall | Draw Kyte-Doolittle hydropathy plot for a protein alignment
wordcount | Count and extract unique words in DNA sequence(s)

## Author(s)

Alan Bleasby (ajb © ebi.ac.uk)
European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SD, UK

## History

Written (Jan 2002) - Alan Bleasby.

## Target users

This program is intended to be used by everyone and everything, from naive users to embedded scripts.

## Comments

None