question about IProphet output

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Andreas Quandt

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Nov 10, 2009, 9:38:10 AM11/10/09
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dear list,

i was wondering if someone could explain me why there are 2 interprophet result entries for each of the 'hit_rank=1' tags in the pep.xml generated by iprophet?

cheers,
andreas

Dave Trudgian

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Nov 10, 2009, 9:49:09 AM11/10/09
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Andreas,

I've just looked at some iprophet .pep.xml files and only see a single
interprophet result entry per search_hit tag.

These files are Mascot, Tandem, OMSSA searches, run individually through
PeptideProphet, combined with iProphet. What workflow gives two tags for
you?

DT
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Dr. David Trudgian
Bioinformatician in Proteomics
University of Oxford

Mon-Thu: CCMP, Roosevelt Drive
Tel: (+44) (01865 2)87784

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Andreas Quandt

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Nov 10, 2009, 10:30:47 AM11/10/09
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hey dave,

i did something similar but combined multiple iprophet pep.xml's (in that case from 3 search engines) to a single iprophet result file.

here an example for a single spectrum

<!-- iprophet.pep.xml generated with mascot -->


<spectrum_query spectrum="B09-10149.c.01821.01821.2" start_scan="01821" end_scan="01821"
                precursor_neutral_mass="958.5047" assumed_charge="2" index="354">
    <search_result>
        <search_hit hit_rank="1" peptide="NIVLLADDS" peptide_prev_aa="K" peptide_next_aa="S"
                    protein="gi|13622159|gb|AAK33905.1|" num_tot_proteins="1" num_matched_ions="3" tot_num_ions="16"
                    calc_neutral_pep_mass="958.4971" massdiff="+0.0076" num_tol_term="1" num_missed_cleavages="0"
                    is_rejected="0" protein_descr="putative lysin - phage associated [Streptococcus phage 370.3]">
            <search_score name="ionscore" value="19.72"/>
            <search_score name="identityscore" value="28.51"/>
            <search_score name="star" value="0"/>
            <search_score name="homologyscore" value="31.32"/>
            <search_score name="expect" value="0.38"/>
            <analysis_result analysis="peptideprophet">
                <peptideprophet_result probability="0.3622" all_ntt_prob="(0.0000,0.3622,0.9790)">
                    <search_score_summary>
                        <parameter name="fval" value="-1.3378"/>
                        <parameter name="ntt" value="1"/>
                        <parameter name="nmc" value="0"/>
                        <parameter name="massd" value="0.008"/>
                        <parameter name="isomassd" value="0"/>
                        <parameter name="pI" value="3.56"/>
                        <parameter name="pI_zscore" value="-1.19"/>
                    </search_score_summary>
                </peptideprophet_result>
            </analysis_result>
            <analysis_result analysis="interprophet">
                <interprophet_result probability="0.0118374" all_ntt_prob="(0,0.0118374,0.495813)">
                    <search_score_summary>
                        <parameter name="nss" value="0"/>
                        <parameter name="nrs" value="0"/>
                        <parameter name="nse" value="0"/>
                        <parameter name="nsi" value="0"/>
                        <parameter name="nsm" value="0"/>
                    </search_score_summary>
                </interprophet_result>
            </analysis_result>
        </search_hit>
    </search_result>
</spectrum_query>


        <!--iprophet.pep.xml generated with xtandem-->

<spectrum_query spectrum="B09-10149.c.01821.01821.2" start_scan="1821" end_scan="1821" precursor_neutral_mass="958.5047"
                assumed_charge="2" index="55" retention_time_sec="854.394">
<search_result>
    <search_hit hit_rank="1" peptide="NLVNGEWK" peptide_prev_aa="K" peptide_next_aa="L"
                protein="gi|13622481|gb|AAK34198.1|"
                protein_descr="putative NADP-dependent glyceraldehyde-3-phosphate dehydrogenase [Streptococcus pyogenes M1 GAS]"
                num_tot_proteins="1" num_matched_ions="14" tot_num_ions="14" calc_neutral_pep_mass="958.4877"
                massdiff="0.017" num_tol_term="2" num_missed_cleavages="0" is_rejected="0">
        <search_score name="hyperscore" value="343"/>
        <search_score name="nextscore" value="296"/>
        <search_score name="bscore" value="1"/>
        <search_score name="yscore" value="1"/>
        <search_score name="expect" value="1.7"/>
        <analysis_result analysis="peptideprophet">
            <peptideprophet_result probability="0.9881" all_ntt_prob="(0.0000,0.6710,0.9881)">
                <search_score_summary>
                    <parameter name="fval" value="1.4464"/>
                    <parameter name="ntt" value="2"/>
                    <parameter name="nmc" value="0"/>
                    <parameter name="massd" value="0.017"/>
                    <parameter name="isomassd" value="0"/>
                    <parameter name="pI" value="6.00"/>
                    <parameter name="pI_zscore" value="0.25"/>
                </search_score_summary>
            </peptideprophet_result>
        </analysis_result>
        <analysis_result analysis="interprophet">
            <interprophet_result probability="0.998354" all_ntt_prob="(0,0.937097,0.998354)">
                <search_score_summary>
                    <parameter name="nss" value="0"/>
                    <parameter name="nrs" value="5"/>
                    <parameter name="nse" value="0"/>
                    <parameter name="nsi" value="0"/>
                    <parameter name="nsm" value="0"/>
                </search_score_summary>
            </interprophet_result>
        </analysis_result>
    </search_hit>
</search_result>
</spectrum_query>


        <!--iprophet.pep.xml generated with omssa-->


<spectrum_query spectrum="B09-10149.c.01821.01821.2" start_scan="1821" end_scan="1821"
                precursor_neutral_mass="958.505004882812" assumed_charge="2" index="1222">
<search_result>
    <search_hit hit_rank="1" peptide="NLVNGEWK" peptide_prev_aa="K" peptide_next_aa="L"
                protein="gi|13622481|gb|AAK34198.1|" num_tot_proteins="1" num_matched_ions="8" tot_num_ions="14"
                calc_neutral_pep_mass="958.487" massdiff="0.017999999999996" is_rejected="0"
                protein_descr="putative NADP-dependent glyceraldehyde-3-phosphate dehydrogenase [Streptococcus pyogenes M1 GAS]"
                num_tol_term="2" num_missed_cleavages="0">
        <search_score name="pvalue" value="0.006009478037955"/>
        <search_score name="expect" value="13.803771053183747"/>
        <analysis_result analysis="peptideprophet">
            <peptideprophet_result probability="0.9829" all_ntt_prob="(0.0000,0.4742,0.9829)">
                <search_score_summary>
                    <parameter name="fval" value="-2.3650"/>
                    <parameter name="ntt" value="2"/>
                    <parameter name="nmc" value="0"/>
                    <parameter name="massd" value="0.018"/>
                </search_score_summary>
            </peptideprophet_result>
        </analysis_result>
        <analysis_result analysis="interprophet">
            <interprophet_result probability="0.997218" all_ntt_prob="(0,0.849045,0.997218)">
                <search_score_summary>
                    <parameter name="nss" value="0"/>
                    <parameter name="nrs" value="5"/>
                    <parameter name="nse" value="0"/>
                    <parameter name="nsi" value="0"/>
                    <parameter name="nsm" value="0"/>
                </search_score_summary>
            </interprophet_result>
        </analysis_result>
    </search_hit>
    <search_hit hit_rank="2" peptide="LNVGFIAPE" peptide_prev_aa="R" peptide_next_aa="T"
                protein="DECOY_gi|13622856|gb|AAK34540.1|" num_tot_proteins="1" num_matched_ions="7" tot_num_ions="16"
                calc_neutral_pep_mass="958.512" massdiff="-0.007000000000005" is_rejected="0"
                protein_descr="DECOY_gi|13622856|gb|AAK34540.1| putative sucrose-specific PTS permease, enzyme II [Streptococcus pyogenes M1 GAS]"
                num_tol_term="1" num_missed_cleavages="0">
        <search_score name="pvalue" value="0.247165546149053"/>
        <search_score name="expect" value="567.739259504375696"/>
    </search_hit>
    <search_hit hit_rank="3" peptide="RAGMPNWQ" peptide_prev_aa="K" peptide_next_aa="I"
                protein="gi|13623019|gb|AAK34688.1|" num_tot_proteins="1" num_matched_ions="8" tot_num_ions="14"
                calc_neutral_pep_mass="958.444" massdiff="0.060999999999996" is_rejected="0"
                protein_descr="gi|13623019|gb|AAK34688.1| hypothetical protein SPy_2006 [Streptococcus pyogenes M1 GAS]"
                num_tol_term="1" num_missed_cleavages="0">
        <search_score name="pvalue" value="0.32298820764574"/>
        <search_score name="expect" value="741.903912962265508"/>
    </search_hit>
    <search_hit hit_rank="4" peptide="NIVLLADDS" peptide_prev_aa="K" peptide_next_aa="S"
                protein="gi|13622159|gb|AAK33905.1|" num_tot_proteins="1" num_matched_ions="7" tot_num_ions="16"
                calc_neutral_pep_mass="958.497" massdiff="0.007999999999996" is_rejected="0"
                protein_descr="gi|13622159|gb|AAK33905.1| putative lysin - phage associated [Streptococcus phage 370.3]"
                num_tol_term="1" num_missed_cleavages="0">
        <search_score name="pvalue" value="0.726627699836322"/>
        <search_score name="expect" value="1669.063826524031356"/>
    </search_hit>
    <search_hit hit_rank="5" peptide="RAVLFQLL" peptide_prev_aa="R" peptide_next_aa="Q"
                protein="gi|13622381|gb|AAK34108.1|" num_tot_proteins="1" num_matched_ions="7" tot_num_ions="14"
                calc_neutral_pep_mass="958.596" massdiff="-0.091000000000005" is_rejected="0"
                protein_descr="gi|13622381|gb|AAK34108.1| conserved hypothetical protein [Streptococcus pyogenes M1 GAS]"
                num_tol_term="1" num_missed_cleavages="0">
        <search_score name="pvalue" value="2.042689741112156"/>
        <search_score name="expect" value="4692.058335334622825"/>
    </search_hit>
    <search_hit hit_rank="6" peptide="LNVISEER" peptide_prev_aa="V" peptide_next_aa="S"
                protein="gi|13622888|gb|AAK34569.1|" num_tot_proteins="1" num_matched_ions="7" tot_num_ions="14"
                calc_neutral_pep_mass="958.509" massdiff="-0.004000000000004" is_rejected="0"
                protein_descr="gi|13622888|gb|AAK34569.1| putative C3-degrading proteinase [Streptococcus pyogenes M1 GAS]"
                num_tol_term="1" num_missed_cleavages="0">
        <search_score name="pvalue" value="4.369044503054501"/>
        <search_score name="expect" value="10035.69522351618798"/>
    </search_hit>
    <search_hit hit_rank="7" peptide="IRGVVFLGV" peptide_prev_aa="K" peptide_next_aa="A"
                protein="DECOY_gi|13621344|gb|AAK33161.1|" num_tot_proteins="1" num_matched_ions="9" tot_num_ions="16"
                calc_neutral_pep_mass="958.594" massdiff="-0.089000000000005" is_rejected="0"
                protein_descr="DECOY_gi|13621344|gb|AAK33161.1| putative fatty acid/phospholipid synthesis protein [Streptococcus pyogenes M1 GAS]"
                num_tol_term="1" num_missed_cleavages="1">
        <search_score name="pvalue" value="10.271567255646678"/>
        <search_score name="expect" value="23593.78998622042127"/>
    </search_hit>
    <search_hit hit_rank="8" peptide="QVRGLEEE" peptide_prev_aa="R" peptide_next_aa="P"
                protein="gi|13621512|gb|AAK33314.1|" num_tot_proteins="1" num_matched_ions="6" tot_num_ions="14"
                calc_neutral_pep_mass="958.473" massdiff="0.031999999999995" is_rejected="0"
                protein_descr="gi|13621512|gb|AAK33314.1| conserved hypothetical protein [Streptococcus pyogenes M1 GAS]"
                num_tol_term="1" num_missed_cleavages="1">
        <search_score name="pvalue" value="10.710793674120096"/>
        <search_score name="expect" value="24602.693069453860517"/>
    </search_hit>
    <search_hit hit_rank="9" peptide="KVQDQDVK" peptide_prev_aa="I" peptide_next_aa="T"
                protein="gi|13622538|gb|AAK34250.1|" num_tot_proteins="1" num_matched_ions="7" tot_num_ions="14"
                calc_neutral_pep_mass="958.509" massdiff="-0.004000000000004" is_rejected="0"
                protein_descr="gi|13622538|gb|AAK34250.1| hypothetical protein SPy_1446 [Streptococcus pyogenes M1 GAS]"
                num_tol_term="1" num_missed_cleavages="1">
        <search_score name="pvalue" value="20.644222337421816"/>
        <search_score name="expect" value="47419.778709057914966"/>
    </search_hit>
    <search_hit hit_rank="10" peptide="ARKEAAKAD" peptide_prev_aa="K" peptide_next_aa="L"
                protein="gi|13621916|gb|AAK33683.1|" num_tot_proteins="2" num_matched_ions="6" tot_num_ions="16"
                calc_neutral_pep_mass="958.52" massdiff="-0.015000000000005" is_rejected="0"
                protein_descr="gi|13621916|gb|AAK33683.1| putative extracellular matrix binding protein [Streptococcus pyogenes M1 GAS]"
                num_tol_term="1" num_missed_cleavages="2">
        <search_score name="pvalue" value="31.424525558323513"/>
        <search_score name="expect" value="72182.135207469109446"/>
    </search_hit>
    <search_hit hit_rank="11" peptide="RGLKQVMK" peptide_prev_aa="N" peptide_next_aa="N"
                protein="gi|13621847|gb|AAK33619.1|" num_tot_proteins="1" num_matched_ions="7" tot_num_ions="14"
                calc_neutral_pep_mass="958.574" massdiff="-0.069000000000005" is_rejected="0"
                protein_descr="gi|13621847|gb|AAK33619.1| hypothetical protein, phage associated [Streptococcus pyogenes M1 GAS]"
                num_tol_term="1" num_missed_cleavages="2">
        <search_score name="pvalue" value="31.947419722034656"/>
        <search_score name="expect" value="73383.223101513605798"/>
    </search_hit>
</search_result>
</spectrum_query>


        <!-- iprophet.pep.xml generated from the previous iprophet.pep.xml's-->

<spectrum_query spectrum="B09-10149.c.01821.01821.2" start_scan="1821" end_scan="1821" precursor_neutral_mass="958.5047"
                assumed_charge="2" index="55" retention_time_sec="854.394">
<search_result>
    <search_hit hit_rank="1" peptide="NLVNGEWK" peptide_prev_aa="K" peptide_next_aa="L"
                protein="gi|13622481|gb|AAK34198.1|"
                protein_descr="putative NADP-dependent glyceraldehyde-3-phosphate dehydrogenase [Streptococcus pyogenes M1 GAS]"
                num_tot_proteins="1" num_matched_ions="14" tot_num_ions="14" calc_neutral_pep_mass="958.4877"
                massdiff="0.017" num_tol_term="2" num_missed_cleavages="0" is_rejected="0">
        <search_score name="hyperscore" value="343"/>
        <search_score name="nextscore" value="296"/>
        <search_score name="bscore" value="1"/>
        <search_score name="yscore" value="1"/>
        <search_score name="expect" value="1.7"/>
        <analysis_result analysis="peptideprophet">
            <peptideprophet_result probability="0.9881" all_ntt_prob="(0.0000,0.6710,0.9881)">
                <search_score_summary>
                    <parameter name="fval" value="1.4464"/>
                    <parameter name="ntt" value="2"/>
                    <parameter name="nmc" value="0"/>
                    <parameter name="massd" value="0.017"/>
                    <parameter name="isomassd" value="0"/>
                    <parameter name="pI" value="6.00"/>
                    <parameter name="pI_zscore" value="0.25"/>
                </search_score_summary>
            </peptideprophet_result>
        </analysis_result>
        <analysis_result analysis="interprophet">
            <interprophet_result probability="0.994754" all_ntt_prob="(0,0.82324,0.994754)">
                <search_score_summary>
                    <parameter name="nss" value="0.6207"/>
                    <parameter name="nrs" value="5"/>
                    <parameter name="nse" value="0"/>
                    <parameter name="nsi" value="0"/>
                    <parameter name="nsm" value="0"/>
                </search_score_summary>
            </interprophet_result>
        </analysis_result>
        <analysis_result analysis="interprophet">
            <interprophet_result probability="0.998354" all_ntt_prob="(0,0.937097,0.998354)">
                <search_score_summary>
                    <parameter name="nss" value="0"/>
                    <parameter name="nrs" value="5"/>
                    <parameter name="nse" value="0"/>
                    <parameter name="nsi" value="0"/>
                    <parameter name="nsm" value="0"/>
                </search_score_summary>
            </interprophet_result>
        </analysis_result>
    </search_hit>
</search_result>
</spectrum_query>
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