Hi Mikael
I'm not too sure about your problem but it may be because you have the non-stereospecific option ticked (hence Hba and Hbb). I always use the stereospecific assignment option and never noticed a problem. Perhaps if you try using this option that will sort out the problem.
Best wishes
Teresa
[log in to unmask]">Hi! I have been assigning side-chain hydrogen peaks and I noticed that beta alpha and beta beta resonances are always swapping when I assign both of them. I have attached two pictures to explain what I mean. In the first picture I have HcccoNH spectrum showing Glu residue. Hydrogen alpha is already assigned. Beta hydrogen peaks Hba and Hbb have not been assigned. One would expect that Hba and Hbb hydrogen peaks would have very similar chemical shifts and this can be see from online data banks (also from Analysis Reference Chemical Shifts). It is hard to distinguish them and they could be either way. So, from the two peak I assigned the lower one (bigger chemical shift) to be Hba. This worked. After this I assigned the upper one as Hbb. Then Analysis swapped the peaks and now they are as shown in picture 2. Is this a bug or something intended? This repeats with other residues as well. Regards, Mikael ######################################################################## To unsubscribe from the CCPNMR list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCPNMR&A=1