Dear All: When I solved the crystal structure of protein, I found a metal binding in it. But however, I can not decide which type of atom it is. I tried ICP-AES and the result suggested the protein contained Ca. I tried to get anomalous signal at the wavelength of 2.07A. And I collected the 360 degree with the spacegroup P6 and the average redundancy is 19.6. But still I can not see the anomalous signal for that metal even I can see clearly the anomalous signal for sulfur. Does anybody have suggestions for me? Thanks in advance.
2009-06-30 xianchidong