Richard, I can’t help you with 5XQL.
However, I can point out a recent structure from my group that might be useful for teaching. The structure was solved by MR with a search model that had 33% sequence identity and represented only 46% of the target structure. The Methods section of the paper has a detailed description of the phasing procedure. We used BALBES, then did autobuilding in phenix from the BALBES/REFMAC map. https://www.ncbi.nlm.nih.gov/pubmed/28420730 John J. Tanner Professor of Biochemistry and Chemistry Chair, Biochemistry Department Graduate Admissions Committee Department of Biochemistry University of Missouri-Columbia 117 Schweitzer Hall 503 S College Avenue Columbia, MO 65211 Phone: 573-884-1280 Fax: 573-882-5635 Email: tanne...@missouri.edu<mailto:tanne...@missouri.edu> http://faculty.missouri.edu/~tannerjj/tannergroup/tanner.html Lab: Schlundt Annex rooms 3,6,9, 203B, 203C Office: Schlundt Annex 203A On Jul 17, 2017, at 11:01 AM, CDaddy <2295867...@qq.com<mailto:2295867...@qq.com>> wrote: I am a structural biologist who is teaching X-ray crystallography. Recently I noticed that BrlR structure (5XQL) was solved using molecular replacement with a search model of very low similarity. I am very interested in this structure because I think this a very good example to show students how to solve phase problem using molecular replacement, especially when the model and the target protein share a low sequence identity. However, when I downloaded the data from PDB, I found that I cannot solve the phase problem using Phaser as mentioned by the authors. During this procedure BmrR (PDB:1R8E) was used as the search model. I tried to consult the authors for help but receive no response by now. Since the description of this issue in the literature is very brief, could anyone please spend a little time on this molecular replacement and give me some advices on this issue? I like to learn some valuable tricks. Your assistance will be highly appreciated. All the best, Richard.