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I am studying the protein backbone dynamics using the standard set of NMR relaxation parameters (R1, R2, NOE). I would like to be sure that there is no aggregation in the sample, and I have doubts about it so far. The best evidence I have is that overall rotational correlation time TAUc, predicted by HYDRONMR, matches exactly the one calculated from averaged R2/R1 values. Can anyone tell me for sure it is enough and I can be sure that protein doesn't form dimers/oligomers?


asked Jun 10 '11 at 03:07

Andrey's gravatar image


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If you extract R2/R1 only from rigid part of your protein, That's sound good because TauC should increase significantly with oligomerization.

Exception can happen, depends on structural state of your protein, for exemple : a random coil monomer have aproximatively the same TauC as his associate globular homodimer...

If you want to be sure about oligomerization, try a size exclusion chromatography or a dynamic light scattering....


answered Jun 10 '11 at 08:01

Yoan%20Monneau's gravatar image

Yoan Monneau

updated Jul 01 '11 at 03:52

Thanks! My protein is quite rigid, and TAUc is the same at different concentrations.. Hope it is good enough! - Andrey (Jun 10 '11 at 09:20)

I say good enough, then. - Paul Driscoll (Jun 13 '11 at 01:50)

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Yes, the value of tau-c can be a good indication of the oligomeric state of your protein. However, it is not absolute proof, as indicated by previous comments in this thread. If you really want a good handle on your protein's oligomeric state, a technique such as SEC-MALS (size exclusion chromatography coupled to multi-angle light scattering), dynamic light scattering, or analytical ultracentrifugation can give you additional evidence.

Good luck.


answered Jun 17 '11 at 09:22

ChemMJW's gravatar image


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