Your native Patterson indicates pseudo C-centering. Are you sure you don’t have space group C222(1)?
If your space group is correct, it’s still pseudo C-centered. You should see that in the intensity-weighted reciprocal lattice. You could try re-indexing on just the most intense spots to give you a data set indexed in a C-centered lattice. Use that data to solve via MR, then convert to the data indexed in the actual space group. Diana ************************************************** Diana R. Tomchick Professor Departments of Biophysics and Biochemistry UT Southwestern Medical Center 5323 Harry Hines Blvd. Rm. ND10.214A Dallas, TX 75390-8816 diana.tomch...@utsouthwestern.edu<mailto:diana.tomch...@utsouthwestern.edu> (214) 645-6383 (phone) (214) 645-6353 (fax) On May 31, 2019, at 3:09 PM, Kevin Jude <kj...@stanford.edu<mailto:kj...@stanford.edu>> wrote: Hello community, I wonder if I could solicit advice about a problematic dataset. I plan to solve the structure by molecular replacement and expect that the protein is relatively compact, ie not elongated. SAXS data supports this expectation. The crystals diffract to 2.6 Å resolution and appear to be in P 21 21 2 with a = 49, b = 67, c = 94, which should fit <=2 molecules in the ASU with 40% solvent. The native Patterson shows a large peak (12 sigma) suggesting a tNCS vector of {0.5, 0.5, 0}. If you're sharper than me, you may have already spotted the problem - c is the long axis of the unit cell, but tNCS constrains the proteins to a plane parallel to the a,b plane. Indeed, molecular replacement attempts using Phaser will not give a solution in any orthorhombic space group unless I turn off packing, and then I get large overlaps in the a,b plane and huge gaps along c. Since I believe that my model is good (or at least the correct shape, based on SAXS), I wonder if I'm misinterpreting my crystallographic data. Any insights into how to approach this problem would be much appreciated. -- Kevin Jude, PhD Structural Biology Research Specialist, Garcia Lab Howard Hughes Medical Institute Stanford University School of Medicine Beckman B177, 279 Campus Drive, Stanford CA 94305 Phone: (650) 723-6431<tel:%28650%29%20723-6431> ________________________________ To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1 ________________________________ UT Southwestern Medical Center The future of medicine, today. ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1
