That worked out, eventually :)

I have an additional question though, which comes from the fact that the 
majority of the known mass shift in my data set has not been fully 
localized on a specific residue, even when spectra look OK-ish.
My background is totally not bioinformatics/statistics, so this could be a 
silly question :) ...

Anyway, is there a reason why the localization of the mass shift is 
performed differently compared the the localization of a known modification?
What I mean is that (as far as I understood), when one wants to perform 
localization on (phospho.STY)PEPTIDE, PTMprophet will simply return T4 as 
the phosphorylated residues (it will not even try to look at D6),
but when trying on (+79.966Da)PEPTIDE, PTMprophet will not focus on just T 
and D, but rather 'look' at the entire sequence.

Wouldn't this 'focusing' speed up the time need for the localization, and 
boost the localization rate?

Thanks
-Piero




On Tuesday, May 22, 2018 at 6:43:33 PM UTC+2, David Shteynberg wrote:
>
> If you are able to build the TPP the code has been checked into the SVN 
> repository.  You can find the code here:
>
>
> https://sourceforge.net/p/sashimi/code/HEAD/tree/trunk/trans_proteomic_pipeline/
>
> If not I can send you a precompiled executable.  Which linux flavor are 
> you using?
>
> -David
>
> On Tue, May 22, 2018 at 5:40 AM, Piero Giansanti <[email protected] 
> <javascript:>> wrote:
>
>> Hello David,
>>
>> Just tried with TPP 5.1.0 (linux), but same problem as you can see below.
>> Is there a way to get hands on the version you have used? :)
>>
>> <spectrum_query start_scan="3214" assumed_charge="2" 
>> spectrum="01928_GA1_P020123_S00_R01_R1.03214.03214.2" end_scan="3214" 
>> index="6" precursor_neutral_mass="1247.5479" retention_time_sec="1120.817">
>> <search_result>
>> <search_hit peptide="GGMNGASPPTSQK" massdiff="0.9869" 
>> calc_neutral_pep_mass="1246.5610" peptide_next_aa="D" 
>> num_missed_cleavages="0" num_tol_term="2" num_tot_proteins="1" 
>> tot_num_ions="24" hit_rank="1" num_matched_ions="10" 
>> protein="sp|Q62234|MYOM1_MOUSE" peptide_prev_aa="R" is_rejected="0" 
>> protein_descr="Myomesin-1 OS=Mus musculus OX=10090 GN=Myom1 PE=1 SV=2">
>> <modification_info modified_peptide="G[58]GM[147]NGASPPTSQK">
>> <mod_aminoacid_mass position="1" mass="58.00836"/>
>> <mod_aminoacid_mass position="3" mass="147.0354"/>
>> </modification_info>
>> <search_score name="hyperscore" value="21.034"/>
>> <search_score name="nextscore" value="18.157"/>
>> <search_score name="expect" value="1.601e-03"/>
>> <analysis_result analysis="peptideprophet">
>> <peptideprophet_result probability="0.9995" 
>> all_ntt_prob="(0.9840,0.9981,0.9995)">
>> <search_score_summary>
>> <parameter name="fval" value="5.8278"/>
>> <parameter name="ntt" value="2"/>
>> <parameter name="nmc" value="0"/>
>> <parameter name="massd" value="0.987"/>
>> </search_score_summary>
>> </peptideprophet_result>
>> </analysis_result>
>> <analysis_result analysis="ptmprophet">
>> <ptmprophet_result prior="0.0769231" 
>> ptm="PTMProphet_ABCDEFGHIJKLMNOPQRSTUVXWYZ0.9869" 
>> ptm_peptide="G(0.000)G(0.000)M(0.000)N(0.000)G(0.000)A(0.000)S(0.000)P(0.000)P(0.000)T(0.000)S(0.000)Q(0.000)K(0.000)">
>> <mod_aminoacid_probability position="1" probability="0.000"/>
>> <mod_aminoacid_probability position="2" probability="0.000"/>
>> <mod_aminoacid_probability position="3" probability="0.000"/>
>> <mod_aminoacid_probability position="4" probability="0.000"/>
>> <mod_aminoacid_probability position="5" probability="0.000"/>
>> <mod_aminoacid_probability position="6" probability="0.000"/>
>> <mod_aminoacid_probability position="7" probability="0.000"/>
>> <mod_aminoacid_probability position="8" probability="0.000"/>
>> <mod_aminoacid_probability position="9" probability="0.000"/>
>> <mod_aminoacid_probability position="10" probability="0.000"/>
>> <mod_aminoacid_probability position="11" probability="0.000"/>
>> <mod_aminoacid_probability position="12" probability="0.000"/>
>> <mod_aminoacid_probability position="13" probability="0.000"/>
>> </ptmprophet_result>
>> </analysis_result>
>> </search_hit>
>> </search_result>
>> </spectrum_query>
>>
>>
>>
>>
>> On Friday, May 18, 2018 at 6:58:36 PM UTC+2, David Shteynberg wrote:
>>>
>>> Hello Piero,
>>>
>>> It appears that the version of PTMProphet in Philosopher is a bit out of 
>>> date.  The latest TPP version is 5.1.0, and PTMProphet has been updated 
>>> with bugfixes and new features in the meantime. I have run my latest 
>>> PTMProphet code (targeted for the 5.2.0 version of TPP) on your data.  For 
>>> the PSMs matching this peptide I cannot replicate the issue you've 
>>> reported.  Instead, PTMProphet seems to be positioning the mass 
>>> modification on the Asparagine in your peptide as you should see in the 
>>> following result file:
>>>
>>>
>>> https://www.dropbox.com/s/z3xf379ulljr3rr/01928_GA1_P020123_S00_R01_R1.PTMPro.pep.xml?dl=0
>>>
>>> Thanks for your interest in PTMProphet.
>>>
>>> Cheers!
>>>
>>> -David
>>>
>>> On Fri, May 18, 2018 at 8:40 AM, Piero Giansanti <[email protected]> 
>>> wrote:
>>>
>>>> Hello David,
>>>>
>>>> I am using PTMprophet via philosopher, and from the xml output it seems 
>>>> it is this version
>>>> TPP v5.0.1 Post-Typhoon dev, Build 201706282113-exported (Linux-x86_64)
>>>>
>>>> Regarding the settings, I am using --massdiffmode --mztol 0.01. The 
>>>> mass tolerance is not exactly the one used for the database search (20 
>>>> ppm), but it should be somehow close to it.
>>>>
>>>> Here https://ufile.io/wiqqb the mzML, pepXML and the output I 
>>>> generated.
>>>>
>>>> Thanks
>>>>
>>>>
>>>> On Friday, May 18, 2018 at 4:21:27 PM UTC+2, David Shteynberg wrote:
>>>>>
>>>>> Hello Piero,
>>>>>
>>>>> Thank you for trying the software.  This is indeed an unusual result.  
>>>>> Can you tell me which version of PTMProphet you are using and how you are 
>>>>> running the tool?  Is it possible for you to post your pepXML file and 
>>>>> data 
>>>>> file online for me to download and test this particular ID?
>>>>>
>>>>> Cheers,
>>>>> -David
>>>>>
>>>>> On Fri, May 18, 2018 at 1:53 AM, Piero Giansanti <[email protected]
>>>>> > wrote:
>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> I am using PTMprophet to localize the set of modifications (i.e. mass 
>>>>>> shifts) identified by running an open search with MSfragger, but I have 
>>>>>> some doubt regarding the interpretation of the output.
>>>>>> In particular, MSfragger identified this peptide
>>>>>> *GG(ox)MNGASPPTSQK*
>>>>>> with a mass shift of 0.9869 Da, which match to the following 
>>>>>> modification according to Unimod
>>>>>> 0.9840:Deamidated (Deamidation), 0.9840:Asn->Asp (Asn->Asp 
>>>>>> substitution), 0.9840:Gln->Glu (Gln->Glu substitution).
>>>>>>
>>>>>> Of these 3 only the first 2 are possible (there is no Q in the 
>>>>>> sequence, so there cannot be any Gln->Glu substitution).
>>>>>>
>>>>>> Now, the output of PTMprophet is as follows:
>>>>>>
>>>>>> *G(0.000)G(0.000)M(0.000)N(0.000)G(0.000)A(0.000)S(0.000)P(0.000)P(0.000)T(0.000)S(0.000)Q(0.000)K(0.000)*
>>>>>>
>>>>>> Is a probability always 0 somehow an expected behavior? How do I 
>>>>>> interpret this? Am I right to say that the 0.9869 Da shift cannot be 
>>>>>> localized to any residues?
>>>>>> My concerns comes from the fact that even if the mod cannot be 
>>>>>> localized, I would have expected to get a probability of (~0.008, i.e. 
>>>>>> 100/length of the peptides) for each residues...
>>>>>>
>>>>>> -- 
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>>>>>>
>>>>>
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>>>
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