[RASMB] AUC Analysis for a protein without tryptophan

[Ewa Folta-Stogniew]

If I were to address a problem like this- I would surely start with 
dynamic light scattering rather than using AUC for screening 
buffers...  especially if you can find the plate reader format DLS 
instrument (unless your protein is really small , i.e. below 10 kDa 
and you cannot get above 0.1 mg/ml,  though you should still be able 
to eliminate the "aggregate forming" buffer conditions by this 
approach).  No absorbance, buffer absorbance etc complication there- 
simple experiment to screen for formation of aggregates.

I would rather use AUC as a secondary screening tool especially given 
the lack of a robust spectroscopic signal.

Ewa

At 07:34 AM 11/26/2009, Ritika Sethi wrote:
>Hi
>
>I am new to this technique.
>My protein precipitates in most of the buffers and one can't go 
>beyond a certain (very low) concentration. I was hoping to screen 
>this protein against different buffers and see micro-aggregates on 
>the AUC and then try different additives to remove the 
>microaggregates. However, I believe its impossible to do so if the 
>protein is without tryptophan.
>
>Any suggestions please?
>
>Thanks
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