[RASMB] Weak association?

[Tom Laue]

Hi Andrew-
It may be due to weak interactions, but the interactions may be coupled 
flow with solvent components. If there are self-interactions, they may 
be of this sort, too, and not what we typically think of as a 
self-association.
I would suggest sedimentation equilibrium measurements as a way to 
eliminate the hydrodynamic nonideality.
Best wishes,
Tom

Leech, AP wrote:
> Hello all,
>
> I have done some SV runs at various concentrations 0.3-10 mg/ml on
> a protein (~14 ka) and the sedimentation coefficient appears to
> remain constant (about 1.58). I had expected it to drop slightly at
> higher concentrations, and so I suspect a weak self association.
> Buffer is NaCl/Tris.
>
> Is it reasonable to try and estimate an association coefficient
> from this sort of data, and what is the best way to do it? (Even
> a lower limit would be acceptable, as the intent is to show that
> dimerisation is not significant).
>
> I'm working my way through Gilbert & Gilbert at the moment (Meth.
> Enzymol vol 27, p273) but is there perhaps something more in the
> "global analysis" line?
>
> All comments appreciated,
>
> Andrew
>

-- 
Department of Biochemistry and Molecular Biology
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