On Fri, 2012-01-06 at 20:40 +0800, LISA wrote:
> Hi all,
>
> I have a DNA binding protein. I get crystals of this protein by
> co-crystallization with different dsDNAs. But all the crystals have
> very poor resolution, about 10-20A. I tried to purify protein-DNA
> complex before setting trays, but it didn't work. Please give me some
> suggestion. Thanks.
>
> lisa
This is quite common with protein-DNA complexes - they tend to exhibit
disorder. Obvious suggestions are to look for a better diffracting
crystal form, and this approach includes varying DNA length. Not sure
if improving crystal quality through dehydration has been tried
extensively for protein-DNA complexes, and frankly I doubt its
potential, but who knows.
But before you throw samples in the sink and curse the darkness, try the
crazy approach of testing ~100 crystals. Worked for us with the TDG -
average crystal diffracts to 10-20A at a synchrotron, but about 1-2% of
them miraculously go to 3A. After all, you only need one "good"
crystal.
Cheers,
Ed.
--
Oh, suddenly throwing a giraffe into a volcano to make water is crazy?
Julian, King of Lemurs
