Dear Stefan,
just saw this after reading post:
http://www.nature.com/nature/journal/v522/n7557/full/nature14559.html
Best, Guenter
> Pramod,
>
> You already got good suggestions on how to handle DNA contamination in protein preparations.
>
> Let me point out briefly that you haven't demonstrated yet that your contamination is DNA.
>
> I had the same observation when purifying UvsX. A very persistent and strong contamination in all my preps at ~500kb. To test weather it was DNA or RNA I boiled the protein 30 minutes and incubated it with DNAase and RNAse and result was the same. I concluded it was neither RNA nor DNA and continued as if nothing had happened.
>
> This publication is reporting the same observation:
>
> Formosa and Alberts (1986) "Purification and characterization of the T4 bacteriophage uvsX protein." J Biol Chem. 1986 May 5;261(13):6107-18.
>
> If you ever find out what it is that runs like 500kb DNA on Agarose, please let me know.
> S.
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