Hi Obayed, you could give in situ protolysis a try. This is where you add a bit of protease along with you target protein to the crystallization drop. It has been quite successful for the folks at the SGC. Here are the relevant references:
Dong A, et al. In situ proteolysis for protein crystallization and structure determination. Nat Methods. 2007 Dec;4(12):1019-21.PMID: 17982461. (http://www.ncbi.nlm.nih.gov/pubmed/17982461) Wernimont A, Edwards A. In situ proteolysis to generate crystals for structure determination: an update. PLoS One. 2009;4(4):e5094. PMID: 19352432. (http://www.ncbi.nlm.nih.gov/pubmed/19352432) good luck, Eric ================================ Eric T. Larson, PhD Biomolecular Structure Center Department of Biochemistry Box 357742 University of Washington Seattle, WA 98195 email: larso...@u.washington.edu ================================ On Mon, 18 Jul 2011, Obayed Ullah wrote:
Hi all I wrote last time but got only one feedback. I know some of you guys must have this experience that how to delete loops from the protein. Please help me with suggestions. I am working with a human protein which have around 20% sequence identity with the other proteins of the same family. Structure of some of the proteins from this family have been solved. All the solved structures have around 20% identity with my protein. I am trying to crystallize the protein but it looks like very hard to get crystal. I have tried different N and C terminally truncated constructs for crystallization but no crystal. My feeling is that probably there is some flexible loops with in the protein which limiting the crystallization. So I want to delete the loops with in the protein (not to truncate in the terminal, I already have done this). I am not asking suggestion about how to delete the loop rather how to decide where the loop is. I am not sure how much it will be helpful to get a homology model of such a protein having low sequence identity. Is there any strategy to decide where the loop could be? Does anybody know any established/ rational method to do that. Waiting for your suggestions Obayed Ullah
