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
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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
