Hi Yu, Have you tried using the Additive Screen (e.g. from Hampton Research) on top of your crystallization condition, and varying the ratio between protein complex and crystallization solution? From the diffraction pattern, it looks you are almost there. Salt crystals don't show spots close to the beam stop usually, so the chance of them being salt crystals is negligible. A little bit of tweaking in crystallization conditions should do the trick. If all this fails, probably, you will have to remove any floppy ends from the proteins in the new constructs. I had a similar experience where the protein with His-tag showed crystals in a lot of conditions but all spherical and cylindrical crystals diffracting to 3.5 A. The protein after removing the His-tag gave crystals that diffracted to 2.4 A.
Good luck! -Gyan On Tue, Feb 13, 2018 at 9:09 AM, Yu Qiu <yu....@sanofi.com> wrote: > Hi, > > > > I have been trying to crystallize a protein complex and keep getting > sphere shape crystals. The diffraction is around 3 angstrom, but looks like > multiple lattices. I am wondering if it could be a quasi crystal? Is there > anyone has such experience? > > > > Thanks, > > Yu > -- Gyanendra Kumar, PhD Associate Scientist, St. Jude Children's Research Hospital, Department of Structural Biology, 262, Danny Thomas Place, MS-311 Memphis, TN 38105 Cell: 631-875-9189 https://www.linkedin.com/in/gyanendrakumar https://scholar.google.com/gyanendrakumar <https://scholar.google.com/citations?user=lnil0IQAAAAJ&hl=en> https://www.researchgate.net/profile/Gyanendra_Kumar3 http://stjude.academia.edu/GyanendraKumar -------------------------------------------------------
