Dear Gong!
Aggregate formation can be prevented by addition of Glycerol upto 0.2M. 20% of Glycerol + Tris 20mM should be good enough. Try to avoid Nacl. High salt conc. for some proteins favor aggregation. Tris is good anough. I know 20% glycerol is bit on higher side. But, I have successfully used this buffer for my protein which was pptg. in Tris 50mM, NaCl 150mM, 0.1%Triton X 100.
While purification on RP-HPLC, the pressure was crossing limits while injection but, decreasing the flow rate, helped solve the pressure problem.
I hope it hepls.
Shifali
On Mon, 01 Jun 2009 19:37:36 +0530 wrote
>Dear all,
>>>>We are having problems to purify a protein due to aggregation. The protein
>is MBP-tagged and stays in solution after the tag is removed. Limited
>proteolysis suggested this protein is mostly folded, with its C-terminal 100
>aa unstructured. However, both the full-length and the truncated versions
>were eluted at the void volume on the S-200 GF column. We suspected that
>this is due to non-specific interactions among molecules that leads to the
>aggregation. Since this protein is a component of a large complex, the
>non-specific interaction might be caused by the exposure of some hydrophobic
>patches. Before we try out different additives, I am wondering whether any
>of you have similar experience? If so, how did you solve the problem. Any
>suggestions are welcome.
>>>>FYI, the buffer we used contains 20mM Tris (pH8), 300mM NaCl, 5% glycerol.
>>>>Best,
>>Gang
>>________________
>>Gang Dong
>>Max F. Perutz Laboratories (MFPL)
>>Vienna, Austria
>>>>>>_______________________________________________
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Shifali Chatrath
Graduate Student
Protein science Lab
Dept. of Biological sciences
National University of Singapore
Singapore
+65-65161210
+65-96393449
