overexpressed protein sometime gives two bands

Yong Jiang yjiang at ucsd.edu
Thu Jan 24 20:12:50 EST 2002


I know that bacterial dnaA proteins have two forms in vivo, ATP form and non
ATP(orADP) form, sometimes I purified DnaA from bacterial and got two bands
which are very closer on SDS-PAGE. I guess you got the two forms of the same
protein.
why don't you do western to confirm it?
good luck
yong

"user" <q6252397 at fernuni-hagen.de> wrote in message
news:a225sc$nf2$1 at f1node01.rhrz.uni-bonn.de...
> Dear all,
>
> I'm overexpressing different proteins (phage, E. cloacae and C. freundii,
> with and without his-Tag) in E. coli.
> Usually I have a good expression and a single band during purification.
> I wonder why I sometimes get two band, which are there all the time during
> purification. They differ only very little in Mw. Probably much less than
5
> kD.
> I suppose, it is the same protein because it seems to bind on the column
> exactly like the "one-band-protein".
>
> Any explanations for this?
>
> TIA,
> Tina
>
>





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