Hello, Regarding your empty Tb site: How similar are the two copies of the protein in the ASU? You can overlay the two individual copies from the ASU to check and see if the binding site without density has been distorted somehow so that it can no longer accomodate the Tb, maybe due to crystal packing, etc.
Mike ----- Original Message ----- From: "Huiming Li" <huimin...@hotmail.com> To: CCP4BB@JISCMAIL.AC.UK Sent: Tuesday, August 9, 2011 9:38:39 AM GMT -08:00 US/Canada Pacific Subject: [ccp4bb] anomalous scatterer Hi All, I am working on a Tb binding protein on which I collected anomalous data at Tb edge of 1.648 A. Each protein is designed to bind one Tb. There are two copies of the protein in an ASU. I have two questions. First, I am only able to see one copy of the protein with Tb bound, and no density on the other copy. Isn't this a bit surprising? Second, there is one additional peak on each monomer at the site where Fe is known to bind, and Fe has an edge of 1.739A. At 1.648A, f' and f'' of Fe is only about 1/5 of Tb. Is it possible Fe also shows some anomalous signal at Tb edge? Thank you, Huiming Li, Ph.D. Immune Disease Institute Children's Hospital Boston Harvard Medical School Boston, MA 02115 -- Michael C. Thompson Graduate Student Biochemistry & Molecular Biology Division Department of Chemistry & Biochemistry University of California, Los Angeles mi...@chem.ucla.edu
