3 bands on WB instead of 1 - (Jan/02/2008 )

Hi there,

I expressed a 6His-tagged protein in E.coli and did a WB against the His tag. The expected protein size incl. signal peptide and His tag is 70400 Da, without signal peptide it would be 68200 Da. I detected these two bands, but I also get a third band at around 46 kDa. Do you know what this band might be? Degraded protein? Modified form of the protein?

Thanks for your suggestions.

chalet2

Yes, I reckon It could be any of the above. Did you include a negative control? Could as well just be a non-specific band...

have you tried non-reducing sds-page? there are artifact bands that appear in the range that you are looking at that i have seen stain non-specifically in westerns.

As a negative control I use samples from "vector only" cultures and I don`t see the additional band there.