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
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....
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.
answered Jun 17 '11 at 09:22