calculate an anomalous map, you should see the Zn signal even if you collected at the SeMet peak. Jürgen ...................... Jürgen Bosch Johns Hopkins University Bloomberg School of Public Health Department of Biochemistry & Molecular Biology Johns Hopkins Malaria Research Institute 615 North Wolfe Street, W8708 Baltimore, MD 21205 Office: +1-410-614-4742 Lab: +1-410-614-4894 Fax: +1-410-955-2926 http://lupo.jhsph.edu
On Oct 30, 2012, at 2:55 PM, Kumar, Veerendra wrote: Dear CCP4bb users, I am working on a Ca2+ binding protein. it has 4-5 ca2+ binding sites. I purified the protein in presence of Ca2+ and crystallized the Ca2+ bound protein. I got crystal and solved the structure by SAD phasing at 2.1A resolution. I can see the clear density in the difference map for metals at the expected binding sites. However I had ZnCl2 in the crystallization conditions. Now i am not sure whether the observed density is for Ca or Zn or how many of them are ca or zn? Since Ca (20 elctron) and Zn (30 electron), is this value difference can be used to make a guess about different ions? is there any way we can find the electron density value at different peaks? Thank you Veerendra
