In order to see the Decoys in your results with non zero problem you either
need two Decoy sets with different prefix or to use option -Od in xinteract.
 On Mar 6, 2015 7:49 AM, "David Shteynberg" <
[email protected]> wrote:

> This seems like a strange problem. Are you describing model estimates or
> Decoy counts here? I would recommend carefully looking at the model to
> decoys FDR plots and the individual models both from PeptideProphet for
> each of the searches and iProphet.  It could be a misbehaving search engine
> or incorrect assumption in the iProphet modeling that would require turning
> off.  I am not sure.  If you can share the data I could explore further.
>
> -David
> On Mar 6, 2015 5:17 AM, "Florian" <[email protected]> wrote:
>
>> Dear list,
>>
>> I am trying to incorporate multiple database search engines and iProphet
>> into my data analysis. I run the TPP from commandline with following
>> commands:
>>
>> 1) For single search engines (here: X!Tandem):
>> xinteract  -Ninteract_xtandem.pep.xml -p0.05 -l7 -OARP -dSHUFFLED
>> -X-m0.02-nK,6.031817-nn,6.031817-H *.pep.xml
>> ProteinProphet interact_xtandem.pep.xml interact_xtandem.prot.xml XPRESS
>> EXCLUDE_ZEROS
>>
>> 2) To use iProphet on this single database search engines:
>> xinteract  -Ninteract_xtandem.pep.xml -p0.05 -l7 -OARP -dSHUFFLED
>> -X-m0.02-nK,6.031817-nn,6.031817-H *.pep.xml
>> c:\Inetpub\tpp-bin\InterProphetParser \Xtandem\interact_xtandem.pep.xml
>> interact.ipro.pep.xml
>> ProteinProphet interact.ipro.pep.xml interact_xtandem.ipro.prot.xml
>> XPRESS EXCLUDE_ZEROS IPROPHET
>>
>> 3) For multiple search engines (here: X!Tandem and MSGF+):
>> c:\Inetpub\tpp-bin\InterProphetParser \Xtandem\interact_xtandem.pep.xml
>> \MSGF\interact_msgf.pep.xml interact.ipro.pep.xml
>> RefreshParser interact.ipro.pep.xml %dbase%
>> ProteinProphet interact.ipro.pep.xml interact_ipro.prot.xml XPRESS
>> EXCLUDE_ZEROS IPROPHET
>>
>> 4) For testing, I also ran ProteinProphet on the combined iProphet output
>> without using the IPROPHET option:
>> c:\Inetpub\tpp-bin\InterProphetParser \Xtandem\interact_xtandem.pep.xml
>> \MSGF\interact_msgf.pep.xml interact.ipro.pep.xml
>> RefreshParser interact.ipro.pep.xml %dbase%
>> ProteinProphet interact.ipro.pep.xml interact_ipro.prot.xml XPRESS
>> EXCLUDE_ZEROS
>>
>> In an example analysis, I identified the following number of Proteins
>> after using <1% FDR based on the ProteinProphet estimation:
>> 1a) X!Tandem only: 3,657 Proteins (589 single hits)
>> 1b) MSGF+ only: 3,791 Proteins (614 single hits)
>> 2a) X!Tandem with iProphet: 3,325 (735 single hits)
>> 2b) MSGF+ with iProphet: 3,473 Proteins (773 single hits)
>> 3) X!Tandem, MSGF+ and iProphet: 3,803 Proteins (964 single hits)
>> 4) X!Tandem, MSGF+ without IPROPHET option: 4,220 proteins (732 single
>> hits)
>>
>> It seems like iProphet reduces the number of protein IDs, while
>> increasing the single hits. So, if I substract the single hits, I even get
>> less protein IDs when using two database search engines instead of one. It
>> even gets worse when I use Myrimatch together with X!Tandem and MSGF+. How
>> can that be? Did I do some obvious mistake here? Or do I have to switch off
>> single models of the iProphet?
>>
>> If not, is it acceptable to use iProphet output without the IPROPHET
>> option in ProteinProphet? This way, I can use multiple search engines and
>> INCREASE my IDs, instead of loosing some.
>>
>> Many thanks!
>>
>>
>>
>>
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