Hello Rajesh We serendipitously encountered three cases where a contaminating fungus led to proteolysis of the proteins, which was required for their crystallization. We identified the fungus by sequencing a little bit of its genome, and found that it is Penicillium!
Here are two of the papers - Mandel CR, Gebauer D, Zhang H, Tong L. (2006). A serendipitous discovery that in situ proteolysis is essential for the crystallization of yeast CPSF-100 (Ydh1p). *Acta Cryst*. *F62*, 1041-1045. Bai Y, Auperin TC, Tong L. (2007). The use of in situ proteolysis in the crystallization of murine CstF-77. *Acta Cryst*. *F63*, 135-138. best regards Liang ---- Liang Tong, William R. Kenan, Jr. Professor and Chair Department of Biological Sciences Columbia University, New York, NY 10027 (212) 854-5203 lt...@columbia.edu http://tonglab.biology.columbia.edu On Fri, Mar 9, 2018 at 3:25 PM, Rajesh < 00001642be9504b8-dmarc-requ...@jiscmail.ac.uk> wrote: > Dear BB, > > I apologize for the off topic. But I strongly believe this is the right > place to ask my question. > > We are working on a protein that is 300 amino acids in length. After many > efforts, we could solve the structure at 1.60 Å resolution. It took > almost 10 months to get this crystal and we could not reproduce it. The > maps are interpretable and we could model only till residue 190 and we > could not see any density for the rest of the molecule. My question is- > Does anyone has encountered such a structure with lots of missing density? > I would appreciate your efforts if someone can send me few references > describing such type of structures. Is there any chance that microbes can > cleave the protein in the crystal drops? > > > > > > Thanks, > > Rajesh.. > >
