Subbu,
Don't forget you crystallization screen can also be used to find a
condition that your protein may be happier in ! As you already have setup a
screen of your protein, have a look at your drops again and see if there
are any conditions that are clear. If so, is there a consistent theme in the
conditions i.e pH or additive ? I've worked with one protein that behaved
similarly and we saw that in drops at pH 5 or below it remained clear. Upon
changing the purification procedure to this lower pH we could concentrate
the protein up to 40 mg/ml (and got nice crystals) instead of the borderline
2mg/ml we were getting at pH 7.4
Goodluck
Stephen
On 21 July 2011 17:53, Narayanan Ramasubbu <[log in to unmask]> wrote:
> Dear All:
> We have been trying to crystallize a protein which is large - > 100 kDa.
> This is soluble but the best we can get is about 1 mg/mL.
> It did crystallize but did not diffract well. Efforts to increase the
> concentration has been unsuccessful. I am wondering whether there are
> methods that others use to increase the concentration other that using
> amicon columns.
> Any help will be appreciated.
> Thanks
> Subbu
>
