Dear Faisal,

you could use Phenix to do an f’’ refinement against the data like described here:

Liu, Q., Liu, Q. & Hendrickson, W. A. (2013). Acta Cryst. D69, 1314-1332.


best regards,

Tobias

On 30 Apr 2014, at 14:01, Faisal Tarique <[log in to unmask]> wrote:

> Dear all
>
> I am working on a metalloprotein which probably contains Ca at its active site..The sulfur containing amino acid constitutes almost 5.4% of the total amino acid residues of this protein..I have collected the data at home source (CuKalpha=1.54A)..Since f'' of Sulfur is 0.56 and that of Ca is 1.28 we can always expect some  anomalous signal out of the data..My question is ..how we will know if the anomalous signal is coming out of Sulfur or from Calcium ?? is there any method through which we can get to know the identity of the scattering molecule through the data..Can FFT anomalous map from CCP4 is of any help in this direction, if yes then please tell me how to interpret the output from this..
>
> --
> Regards
>
> Faisal
> School of Life Sciences
> JNU
>