Hi,
we seem to be tying ourselves in knots with a project where we have one
protein in two different environments and then want to compare shifts.
Part of the problem is that I am not quite sure how Analysis expects us
to organise the data in such a situation, so it is difficult to know
where something has gone wrong.
Currently our project organisation is as follows:
Molecular system 1, chain A - Native Protein
Molecular system 2, chains A, B and C - Oxidised Protein (which contains
multiple peak sets for some residues, hence the use of 3 chains)
The student working on this project had a lot of trouble sorting out all
the assignments. What she seems to have now ended up with is different
resonances for the different spin systems and chains. However, in the
Resonances pop-up (see attached) there are also some resonances which
are doubled up. There are some which appear to be linked to peaks, and
yet the little "E" in the Shift box suggests the chemical shift is
editable which doesn't make sense to me. I can't quite see how we can
get rid of these (as they are currently messing up our shift differences
calculations).
My guess is that Analysis actually wants us to use the same resonance
across different Molecular Systems and Chains. Though presumably this
will then mean that a single resonance will appear multiple times in the
Resonances table (when selecting "Any Shift List")?
So the question is how we get out of this mess. Are we going to have to
find some way of reassigning the shifts in MS2 to the same resonances
already used in MS1? Or do we need to find a way of removing the
spurious doubled resonances? And in either situation, how do we do this?
I'd be grateful for any suggestions.
Thanks,
Vicky
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Dr. Victoria A. Higman-Davies
School of Chemistry
University of Bristol
Cantock's Close
Bristol BS8 1TS
U.K.
E-mail: [log in to unmask]
http://www.protein-nmr.org.uk
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