I have picked 3D NOESY/TOCSY and using the 1H/1H plane all looks fine. The 15N(x)/1H(y) plane however shows peaks that are not in that plane. For example, an isolated peak in the HSQC is at 9.3 ppm and I can see the peaks (but not contours) for another NH that is at 9.1 ppm. All the 3Ds have the same resolution, I have the acquisition dimension in the Z axis (to look for NH-NH return peaks) and there are 0.008 ppm/point. I am only viewing one plane in the 1H dimension. Screenshot attached @70 in this plane, and @116 with no contours but a load of peaks.
Any chance of some help with this? It pretty much makes V3 unusable for working with 3D 15N-based assignment.
Hi Helen,
We have this on the bug tracker as something to fix since your original post but it doesn’t seem to have hit the top of the priority list yet - it will.
In the meantime, to look for your return peaks have you tried using an HNH view (create by flipping the y & z axes from one of your HHN strips) and then navigating to it from the diagonal peak you’re checking out so that z dimension is set to your 1H shift. You should see an HSQC-like slice through the 3D with all possible return peaks visible. You can display your HSQC in the same window to see the relevant assignments too.
Thanks Brian, it’s a workaround for NH-NH based assignment at least but not for resolution of overlapped peaks. At least it’s on the list I guess.
Hi Helen,
I’m really sorry - this one rather passed me by. Could you send me your project and spectra and I’ll take a closer look at this?
Also: for 15N based assignment, have you had a look this macro: Match 15N-Noesy peaks - CCPN ? You might find it helpful.
Thanks,
Vicky
Hi Helen,
sorry about this one. Should now be fixed and on the update server.
Vicky