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!




-- 
You received this message because you are subscribed to the Google Groups 
"spctools-discuss" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to [email protected].
To post to this group, send email to [email protected].
Visit this group at http://groups.google.com/group/spctools-discuss.
For more options, visit https://groups.google.com/d/optout.

Reply via email to