Hi Matt,

I think you have helped to clarify another issue which i posted
earlier:
http://groups.google.com/group/spctools-discuss/browse_frm/thread/6aa0ae195b29adde?hl=en

My data was also not centroided, since it is not working in MassWolf
4.2.1. Hence I believe what you said about XTandem not designed to run
on profile mode data, explains why my Xtandem searches assigns certain
doubly charged peptides as +1 or +3 charge states. This should occur
for those lower intensity hits.

Thanks, guys!


Bernt


On Jul 16, 2:46 am, Matthew Chambers <[email protected]>
wrote:
> Hi Chris,,
>
> AFAIK, X! Tandem isn't designed to run on profile mode data. If you are
> using the default "total peaks" setting then it will take only the 50
> most intense samples (not peaks, because it assumes every data point is
> a peak). 50 samples are easily consumed by just a few peaks. You can
> increase the total peaks setting, but I expect that would kill the score
> discrimination because it's designed to look at peaks instead of
> samples. You should continue to acquire centroided MS/MS data or at
> least have some way to centroid it post-acquisition before sending it to
> X! Tandem.
>
> -Matt
>
> chr12is wrote:
> > Greetings,
>
> > I am encountering an error which I dont remember having troubles with
> > before. I used to acquire my data such that in MS/MS mode it would be
> > centroided, as in older versions of the TPP, filesizes over 4gb were
> > problematic. Since I have noticed this isnt a problem anymore in the
> > newer TPP versions, I am using 4.2.1, I have started acquiring in
> > continuum mode again for MS/MS. I have MassLynx 4.1 installed, and
> > have run centroided MS/MS files through the TPP on this computer with
> > no problems.
>
> > However, if I take one of my new continuum files, it converts in
> > masswolf with no errors, I am not centroiding in masswolf, or using
> > gzip. When I take it to XTandem it gives me this error:
>
> > X! TANDEM 2 (2007.07.01.3)
>
> > Loading spectra ...
> > This application has requested the Runtime to terminate it in an
> > unusual way.
> > Please contact the application's support team for more information.
>
> > Any ideas whats happening?

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