Thank You very much everyone. I took all your suggestions into consideration. I was able to solve the problem
Thank You once again Deepthi On Tue, Aug 28, 2012 at 5:07 PM, Pavel Afonine <pafon...@gmail.com> wrote: > Hi Deepthi, > > 1) refine anisotropic ADPs for Zn, > 2) make sure charge is accounted for, > 3) refine f' and f'' for Zn (that means you need to use anomalous data in > refinement). > > If 1-3 do not help, add > > 4) refine occupancy of Zn, > 5) make sure you visualize your map using correct levels. > > This should solve the problem. > > Pavel > > > On Tue, Aug 28, 2012 at 10:44 AM, Deepthi <deept...@gmail.com> wrote: > >> Hi everybody, >> >> I am working on a mutant protein structure which is 56 aminoacids long >> and solved the structure using SAD( Single wavelength anomalous >> dispersion) with zinc ions. We used SHELX software to locate the Zinc atoms >> and solved phases. We got the structure as a monomer. The resolution of the >> structure is 1.4 A0 . >> >> The problem with the structure is, when i calculate the structure factors >> in COOT it always shows negative electron density around ZINC atoms which >> have been located by SHELX. >> >> I initially thought it was because my COOT software was very old and it >> doesn't recognize the Zinc atoms( I am new to crystallography) . I >> calculated the structure factors using FFT from CCP4 and it shows the same. >> I don't understand the problem. It refines well in Refmac and B-factors >> also look very good. >> >> Anyone know what the problem is? >> >> Thank You in advance >> Deepthi >> >> -- >> Deepthi >> > > -- Deepthi
