Dear Lieven,
I wonder if this may have arisen because you had both spectra showing
when you were picking peaks.
When you pick peaks, these are picked in all spectra which are showing
in that window (i.e. which are 'on' in the toolbar). Thus if you were
picking a peak in the HNCO at 165 ppm and the HNCACB was also selected
(but not directly visible because it was shown at a different ppm
range), this peak may have also been placed in the HNCACB spectrum.
Analysis will have noticed this at some stage and then expanded the
HNCACB aliased range to go down to 165 ppm. The same thing may have
happened the other way round, too, meaning that your HNCO is shown at
low ppm values. So it may be worth checking whether you have incorrect
peaks in your spectra at these high/low ppm values which should only be
on in one and not two spectra. If you remove those and then change your
aliased ranges back to what they were, hopefully you will be rid of your
doubled spectra. When picking peaks by hand, always make sure that only
the spectrum which you want to pick is selected in that window - easily
forgotten, though, as I find myself from time to time :) .
Vicky
Lieven Buts wrote:
> Hello all,
>
> I am pretty new to macromolecular NMR in general and the
> CCPNMR programs in particular, so bear with me :-) . I think
> I am also seeing the spectrum duplication issue.
>
> I am working on some triple-resonance spectra of a small
> protein, and I am looking at (among others) a HNCACB and
> and a HNCO spectrum in a 3D window with 1H, 13C and 15N
> axes. The HNCACB spectrum has 13C frequencies in the
> range from 8 to 88 ppm, while the HNCO spectrum ranges
> from 165 to 185 ppm.
>
> While picking and assigning peaks, a second copy of the
> HNCACB spectrum appeared, with the frequency range shifted
> to 88-165 pm (fitting snugly between the proper limits
> of the two spectra). Some time later, six equally-spaced
> "ghost images" of the HNCO spectrum appeared, with the
> top one reaching up to 50pm on the 13C axis.
> (Image at http://ultr23.vub.ac.be/~lieven/spectra.png )
>
>
--
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Dr. Victoria A. Higman
Leibniz-Institut fuer Molekulare Pharmakologie (FMP)
NMR-Supported Structural Biology
Robert-Roessle-Str. 10
13125 Berlin
Germany
Phone: +49-30-94793 223
E-mail: [log in to unmask]
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