Hi Kristina, I am not so sure about answers to your questions. It would be
ideal to use SpectraST 5.0 in all your processing if you can easily do
this, yes, but in some cases it would not matter much. In general, where
peak interpretation is involved, SpectraST 5.0 is better. But I don’t know
relative to what you’re doing exactly when peak re-interpretation happens.



Can you just rebuild all your libraries with SpectraST 5.0? That would be
safest.



Regards,

Eric







*From:* [email protected] <[email protected]>
*On Behalf Of *Kristina Plate
*Sent:* Monday, September 23, 2019 4:22 AM
*To:* spctools-discuss <[email protected]>
*Subject:* Re: [spctools-discuss] Combination of consensus libraries and
import in MRM format via spectraST



Hi Eric,



thank you very much for your reply and the detailed and, yes, quite
reasonable explanation. Some of the spectral libraries I got for the
combination were built with SpectraST 4.0 and the remaining builds as well
as the combination and further import steps were done with SpectraST 5.0.
But there are two factors bothering me:



1. I thought too, that the "issue" is caused by different SpectraST
versions. But when I did the MRM import (spectraST 5.0) on the single
spectral libraries which were built with the older version (see above),
this phenomenon didn't occur.



2. Even if it's explainable by a smarter interpretation by SpectraST, does
that mean that I can use these changed spectra or is it questionable to use
spectral libraries of older software versions imported with a newer one?



Thank you and kind regards,

Kristina

Am Freitag, 20. September 2019 20:49:28 UTC+2 schrieb Eric Deutsch:

Hi Kristina, I’m not certain I fully understand your issue, but maybe I can
answer some questions:



Partial old:

Name: DIETIIQK/2 *(old entry, original library)*

308.1581  226.5     ?

309.0826  359.4     ?

325.6734  1596.8    b6-35^2/0.000,b6-36^2/0.492

329.1945  141.2     a6^2/0.000

343.1920  668.4
b6^2/0.000,y3-45/-0.042,y6-45^2/-0.516,y6-46^2/-0.024



Partial new:

Name: DIETIIQK/2 *(new entry, combined library)*

308.1581  226.5     ?

309.0826  359.4     ?

326.1680  1596.8    ?

328.2231  141.2     m4:6/0.000

344.1816  668.4     m3:5/0.000



The first two peaks are fine. For the third entry, I am guessing that in
the original library this peak got shifted to exact m/z of the presumed
interpretation b6-35^2. But this is a highly unlikely interpretation. So in
the new entry, that peak retains its original m/z (i.e. not snapped to a
presumed interpretation) and a “?”. SpectraST seems to be smarter about not
assigning a silly interpretation.



For the next peak with intensity 141.2, the old library had an
interpretation of a6^2 and the m/z is snapped to that interpretation. But
a6^2 is a super unlikely interpretation, or maybe let’s call it impossible
and wrong. In the new library, this same peak has been interpreted as an
internal fragmentation ion and the m/z has been snapped to that. The m4:6
means that the peptide was fragmented in two places such that you get a
little ion that is TII and has a charge so you see it. Internal
fragmentation turns out to be fairly common and so m4:6 is far more
plausible an interpretation than a6^2. Same for m3:5 (ETI). Not necessarily
correct, but far more plausible than an a6^2 and a b6^2.



So I’m guessing that the first spectrum comes from a version where internal
fragmentation was not yet supported, and the second spectrum comes from a
newer version of SpectraST that knows about internal fragmentation and
interprets peaks better.



Does that seem like a reasonable explanation of what’s going on? Henry
might know more.



Regards,

Eric













*From:* [email protected] <javascript:> <
[email protected] <javascript:>> *On Behalf Of *Kristina Plate
*Sent:* Friday, September 20, 2019 6:22 AM
*To:* spctools-discuss <[email protected] <javascript:>>
*Subject:* [spctools-discuss] Combination of consensus libraries and import
in MRM format via spectraST



Hello again,



as I described before (topic: *What happens during consensus building?*) I
have a problem with some messed up spectra in my spectral libraries.

I combined four spectral libraries and built consensus spectra. Afterwards
I reimported the combined consensus spectral library in MRM format and
converted it in an assay library. When I checked the SPTXT file I found
some *slightly changed spectra* and new *"ion types" m*. Please see my
example of an old, normal spectrum and the corresponding new one below:



Name: DIETIIQK/2 *(old entry, original library)*

LibID: 4160

MW: 960.5481

PrecursorMZ: 480.2740

Status: Normal

FullName: X.DIETIIQK.X/2 (CID-QTOF)

Comment: AvePrecursorMz=480.5611 BinaryFileOffset=23385298
FracUnassigned=0.09,1/5;0.23,11/20;0.06,7/31 MassDiff=-0.0014 Mods=0 NAA=8
NISTProtein=Id_02 NMC=0 NTT=1 Nreps=1/1 OrigMaxIntensity=11 Parent=480.274
Pep=Tryptic PrecursorIntensity=0 Prob=1.0000 Protein=1/Id_02
RawSpectrum=file_02_04.69683.69683 RetentionTime=2745.2,2745.2,2745.2
Sample=1/sample_02,1,1 Se=1^C1:pb=1.0000/0,fv=2.7040/0 Spec=CREATE
TotalIonCurrent=8.9e+003 iRT=33.4,33.4,33.4

NumPeaks: 31

308.1581  226.5     ?

309.0826  359.4     ?

325.6734  1596.8    b6-35^2/0.000,b6-36^2/0.492

329.1945  141.2     a6^2/0.000

343.1920  668.4
b6^2/0.000,y3-45/-0.042,y6-45^2/-0.516,y6-46^2/-0.024

353.2183  967.7     y3-35/0.000

354.2183  480.9     y3-35i/0.000

355.2183  481.6     y3-35i/0.000

358.1609  442.5     b3/0.000,y6-17^2/0.456,y6-18^2/0.948

358.1970  96.7 ?

365.2030  293.0     ?

373.2367  296.2     ?

388.2554  1744.6    y3/0.000,b7-36^2/-0.955

424.1714  315.8     b4-35/0.000,b4-36/0.984

442.1820  644.1     b4-17/0.000,b4-18/0.984

457.7633  546.4     p-45^2/0.000,p-46^2/0.492,y4-44/0.414

458.2791  109.5     p-44^2/0.000,b4/-0.929

471.7608  110.9     p-17^2/0.000,p-18^2/0.492

472.2608  111.1     p-17^2i/0.000

477.1321  111.6     ?

480.2740  336.0     p^2/0.000

484.3130  224.9     y4-17/0.000,y4-18/0.984

501.3395  523.5     y4/0.000

553.1674  240.4     ?

567.3501  487.3     y5-35/0.000

584.3766  247.1     y5-18/0.000

602.3872  2935.1    y5/0.000

696.3927  205.5     y6-35/0.000,y6-36/0.984

714.4032  2211.4    y6-17/0.000,y6-18/0.984

731.4298  10000.0   y6/0.000

732.4298  414.9     y6i/0.000



Name: DIETIIQK/2 *(new entry, combined library)*

LibID: 4673

MW: 960.5481

PrecursorMZ: 480.2740

Status: Normal

FullName: X.DIETIIQK.X/2 (CID-QTOF)

Comment: AvePrecursorMz=480.5611 BinaryFileOffset=20613807
FracUnassigned=0.09,1/5;0.25,13/20;0.17,13/31 MassDiff=-0.0014 Mods=0 NAA=8
NISTProtein=Id_02 NMC=0 NTT=1 Nreps=1/1 OrigMaxIntensity=11 Parent=480.274
Pep=Tryptic PepContext=1/NTPR_DIHE PrecursorIntensity=0 Prob=1.0000
Protein=1/Id_02 RawSpectrum=file_02_04.69683.69683
RetentionTime=2745.2,2745.2,2745.2 Sample=1/sample_02,1,1
Se=1^C1:pb=1.0000/0,fv=2.7040/0 Spec=CREATE TotalIonCurrent=8.9e+003
iRT=33.4,33.4,33.4

NumPeaks: 31

308.1581  226.5     ?

309.0826  359.4     ?

326.1680  1596.8    ?

328.2231  141.2     m4:6/0.000

344.1816  668.4     m3:5/0.000

353.2183  967.7     y3-35/0.000

354.2183  480.9     y3-35i/0.000

355.2183  481.6     y3-35i/0.000,m5:7/-0.016

358.1609  442.5     b3/0.000

358.1970  96.7 ?

365.2030  293.0     ?

373.2367  296.2     ?

388.2554  1744.6    y3/0.000

424.1714  315.8     b4-35/0.000

441.1980  644.1     b4-18/0.000

457.2713  546.4     p-46^2/0.000,m3:6/0.006

459.2086  109.5     b4/0.000

471.2688  110.9     p-18^2/0.000

472.2512  111.1     ?

477.1321  111.6     ?

480.2410  336.0     ?

484.3130  224.9     y4-17/0.000

501.3395  523.5     y4/0.000

553.1674  240.4     ?

568.3124  487.3     ?

584.2763  247.1     ?

602.3872  2935.1    y5/0.000

695.4087  205.5     y6-36/0.000

713.4192  2211.4    y6-18/0.000

731.4298  10000.0   y6/0.000

732.4675  414.9     ?



I assumed before, that it was an issue with the consensus building, but I
figured out that it took action during the *import via spectraST into MRM
format*.



Now, I just saw that I don't have this problem when I use the single
libraries. Even with consensus libraries built with with an older spectraST
version the MRM import works just fine.

Maybe there is the *problem in the combination of the spectral libraries?*
I already got them as single consensus libraries and combined them with the
following command



spectrast -cNcombined_lib -cd -cu -cr1 -cy1 -cAC -cJU
Lib_01.splib Lib_01.splib Lib_01.splib Lib_01.splib



Could this be an issue here. Do I have to rebuild all libraries before
combining them?



I would be really happy about any suggestions. Thank you in advance!



Kind regards,

Kristina

____________________

Kristina Plate, MSc. Biomathematics



University of Greifswald

Center for Functional Genomics of Microbes

Institute for Microbiology

Department of Microbial Proteomics

Felix-Hausdorff-Str. 8

17489 Greifswald



phone:   +49 3834 420-5925

fax: +49 3834 420-5902

-- 
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] <javascript:>.
To view this discussion on the web visit
https://groups.google.com/d/msgid/spctools-discuss/1573a2bc-1b4a-4ca7-bc88-75579028df95%40googlegroups.com
<https://groups.google.com/d/msgid/spctools-discuss/1573a2bc-1b4a-4ca7-bc88-75579028df95%40googlegroups.com?utm_medium=email&utm_source=footer>
.

-- 
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 view this discussion on the web visit
https://groups.google.com/d/msgid/spctools-discuss/d206982e-1892-494c-8762-0c519ae3b10c%40googlegroups.com
<https://groups.google.com/d/msgid/spctools-discuss/d206982e-1892-494c-8762-0c519ae3b10c%40googlegroups.com?utm_medium=email&utm_source=footer>
.

-- 
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 view this discussion on the web visit 
https://groups.google.com/d/msgid/spctools-discuss/749268edd4136e4cc306381eecf6b5d4%40mail.gmail.com.

Reply via email to